Updated at 4:47 p.m.

President Obama blamed Russia for the violence in Ukraine and said its "incursion" into the former Soviet state will only carry additional costs.

"Russia has deliberately and repeatedly violated the sovereignty and territorial integrity of Ukraine, and the new images of Russian forces inside Ukraine make that plain for the world to see," Obama said at a White House news conference on Thursday.

Update at 5:00 p.m. ET

After being halted at the border for more than a week, a Russian aid convoy is rumbling into eastern Ukraine without permission, prompting Kiev to label the move a "direct invasion" of sovereign territory.

Karoun Demirjian, reporting for NPR from Moscow, says 150 Russian trucks arrived in the rebel-held city of Luhansk on Friday.

Russia and Ukraine are holding large military exercises along their shared border as the Ukrainian military claims to be closing in on rebel strongholds in Donetsk and Luhansk, NPR's Karoun Demirjian reports from Moscow.

Government troops and separatists have been fighting for months for control of eastern Ukraine, Karoun says, and Ukrainian leaders say Russia has been supplying the separatists with weapons and strategic assistance — a charge Moscow denies.

Ukrainian forces were reportedly advancing on rebel positions near the key eastern town of Donetsk on Saturday, as they try to retake the separatist stronghold.

Donetsk is the region where Malaysia Airlines MH17 was shot down on July 17, killing nearly 300 people. Pro-Russian rebels have been blamed for downing the plane and they have hampered international efforts to access the site of the wreckage.

The U.S. says it has "new evidence" that Russian forces have been firing artillery across the border to attack Ukrainian military positions, and that Moscow is planning to ship powerful rocket artillery to the rebels it backs in the country's east.

"We have new evidence that the Russians intend to deliver heavier and more powerful multiple rocket launchers to the separatist forces in Ukraine, and have evidence that Russia is firing artillery from within Russia to attack Ukrainian military positions," State Department spokeswoman Marie Harf said during a daily briefing.

A refrigerated train carrying the remains of the people who died aboard the downed Malaysia Airlines plane arrived in Kharkiv, Ukraine, on Tuesday. That's a city controlled by the central government in Kiev and 17 hours away from the chaos of Hrabove, the eastern city controlled by pro-Russian separatists, where the debris and remains were scattered.

The New York Times sets the scene:

This post was last updated at 7:10 p.m. ET.

Pro-Russian separatists have given what they say are Malaysia Airlines Flight MH17's data recorders to Malaysian officials in Donetsk, the city in eastern Ukraine that has been the militants' stronghold.

Along with the release of victims' bodies hours earlier, the transfer of the black boxes fulfills part of a deal Malaysian Prime Minister Najib Razak said he had reached with the rebels Monday.


On Monday at the White House, President Obama urged Russian President Vladmir Putin to order Russian separatists in Ukraine to allow international investigators unfettered access to the crash site of Malaysian Airlines Flight MH17. 

Pete Souza / White House

President Barack Obama spoke about the downed plane in eastern Ukraine from the White House Monday morning. He called for international investigators to have "immediate and full access" to the site where a passenger jet was shot down last week.

U.S. officials have been seeking to build a case that the plane was shot down by pro-Russian separatists.

(This post was updated at 12:51 p.m. ET.)

Russian President Vladimir Putin says tragedies such as the downing of Malaysia Airlines Flight MH17 last week should "bring people together" rather than "dividing us."

Updated at 4:25 p.m. ET.

In the most emphatic U.S. statement to date on culpability for the downing of a Malaysian airliner over Eastern Ukraine that killed 298 people, Secretary of State John Kerry says evidence overwhelmingly points to Russian-backed separatists.

In an interview with CNN, he says that U.S. intelligence, as well as social media put out by the rebels, "obviously points a very clear finger at the separatists.

Updated at 2:55 p.m. ET.

Moscow has issued a quid pro quo for sanctions imposed on it by Washington, banning a U.S. congressman and 12 other Americans from entering Russia.

NPR's Hansi Lo Wang reports that the Foreign Ministry in Moscow says the new blacklist is in response to U.S. visa restrictions on Russian citizens in the wake of Moscow's annexation of Crimea and its continuing support for separatists in eastern Ukraine.

Updated at 4:35 p.m. ET.

International investigators say armed rebels have limited their inspection of the Eastern Ukraine site of the downed Malaysian Airlines flight that killed nearly 300 passengers and crew, as Kiev accused pro-Russian separatists of destroying evidence at the scene.

This post was updated at 5:00 p.m. ET.

White House

President Barack Obama said one American was killed on a downed plane in Ukraine on Thursday, and that the airliner was shot down by a surface-to-air missile in an area controlled by Russian-backed separatists. He called for an immediate ceasefire in Ukraine, where he said heavily armed and trained separatists receive Russian support.

This post was last updated at 6:40 p.m. ET.

A Malaysia Airlines Boeing 777 with 298 passengers and crew aboard has crashed in eastern Ukraine in an area of the country that has been wracked by a separatist insurgency.

This post updated at 10:15 a.m. ET.

A Ukrainian government spokesman says one of its warplanes was shot down in the country's east by a Russian air force jet, as the U.S. and Europe stepped up sanctions on Moscow over its support of separatist rebels.

President Obama outlined a new package of sanctions against Russian firms and individuals on Wednesday.

"These sanctions are significant but also targeted," Obama said. "Russia will see that its actions in Ukraine have consequences."

The administration targeted large banks, as well as energy and defense firms. The sanctions stopped short of covering entire sectors of the Russian economy.

Obama said they were designed to inflict pain on Russia without harming U.S. companies or the nation's allies.

The area of Russia is said to be called, ominously enough, the end of the world. And that's where researchers are headed this week, to investigate a large crater whose appearance reportedly caught scientists by surprise. The crater is estimated at 262 feet wide and is in the northern Siberian area of Yamal.

An exchange of mortar fire has been reported in eastern Ukraine, where government troops and pro-Russian separatist forces had been observing an uneasy cease-fire in the past week. The news comes as Secretary of State John Kerry says Russia could face sanctions if it doesn't help end the violence.

Russian state news media are reporting explosions near the airport in the eastern Ukrainian city of Kramatorsk, where the armed groups reportedly absorbed and returned mortar fire. Similar clashes were reported earlier this week.

President Obama said today [Tuesday] that he wants to boost the U.S. military presence in Europe amid simmering tensions with Russia over its actions in Ukraine.

Militants in Ukraine shot down a military helicopter near the eastern city of Slovyansk Wednesday, killing 14 soldiers that included an Army general. The incident comes days after Ukraine stepped up its operations against pro-Russian rebels this week.

From Kiev, NPR's Peter Kenyon reports for our Newscast unit:

Pro-Russian rebels who had taken over an international airport in Donetsk have been pushed back, Ukraine's government says. Violent clashes erupted Monday and Tuesday; at least 35 people have died.

From Kiev, NPR's Peter Kenyon reports for our Newscast unit:

"The battle for Donetsk airport appears to symbolize the government's tougher stance on the pro-Russian insurgents in the east. Using fighter jets and helicopter gunships, the military says it has retaken control of the airport, though rebels dispute that claim.

Pro-Russian separatists attacked a military checkpoint in eastern Ukraine on Thursday, killing at least 13 soldiers and wounding about 30, according to Ukraine's acting prime minister. The country is preparing to hold national elections on Sunday.

A separatist commander told The Associated Press that one of his men also died.

The attack took place near the village of Blahodatne in Donetsk, one of two main areas in eastern Ukraine where separatists say they want to break away from the country and its interim government.

When Russian President Vladimir Putin started vilifying the U.S., and state-controlled media took his cue, Michael McFaul was portrayed as one of the American villains. McFaul was the American ambassador to Russia from January 2012 to February of this year. He planned to leave just after the Sochi Olympics, which ended up coinciding with the Ukrainian Parliament voting to remove President Viktor Yanukovych from office, leading to Russia's annexation of Crimea.

If Russia was aiming to target one of Ukraine's vulnerabilities, natural gas would be the bull's-eye. Ukraine gets about 60 percent of its gas from Russia.

Clifford Gaddy, a Russia specialist at the Brookings Institution, says as the dispute between the two countries grows, Moscow is more willing to use natural gas as a weapon.

A referendum on independence from Ukraine shows strong support for secession, according to separatist leaders in the districts where Sunday's vote was held. Kiev and Western governments say the vote is illegitimate.

Russia, which has been accused of orchestrating the unrest in eastern Ukraine, says it "respects the expression of will of the population of the Donetsk and Luhansk regions." But the Kremlin's statement also called for dialogue with Kiev, not violence.

It's a day for patriots in Russia, where the country is celebrating Victory Day to commemorate the World War II defeat of Nazi Germany. A parade of troops, tanks and missile launchers made its way through Red Square to mark the occasion.

"It is a holiday when an overwhelming force of patriotism triumphs, when all of us feel particularly acutely what it means to be loyal to the motherland and how important it is to defend its interests," President Vladimir Putin said.

Urging the release of separatists detained during Friday's unrest that left dozens dead, more than 100 pro-Russia activists surrounded a police station in the southern Ukrainian port city of Odessa Sunday.

Update at 4:30 p.m. ET: More Activists Released

Police in Odessa say 67 pro-Russia activists were freed Sunday.

CNN quotes the Ukrainian Interior Ministry's website:

The Ukrainian government is describing its offensive against pro-Russian separatists in the eastern part of the country as an "anti-terrorist operation," language that offends the separatists and Russia.

In turn, Russia is using even stronger language, saying that the Ukrainian military has launched a "punitive operation." While that may not carry any special meaning to Western ears, it has far more sinister implications for Russians.