Russia-Ukraine war: Key things to know about the conflict

The Russian invasion of Ukraine entered its third week on Thursday with Russian forces continuing to bombard major cities and desperate civilians hoping to escape through agreed-upon safe corridors.

Thousands of people have been killed and more than 2 million have fled the country since Russian troops crossed into Ukraine on Feb. 24. Besieged cities have been suffering from shortages of food, medicine, heat and electricity, and thousands of trapped civilians were hoping to leave Thursday during temporary cease-fires the two sides agreed to — though most past attempts failed because of continued shelling.

The top diplomats from Russia and Ukraine met for the countries' highest-level talks since the start of the invasion, but they weren't able to find common ground.

And world leaders continued to condemn the Russian airstrike on a maternity hospital in the port city of Mariupol that killed three people, including a child.

Here are some key things to know about the war:

WHAT HAS THE AP DIRECTLY WITNESSED OR CONFIRMED?

Russia continued its heavy bombardment of Mariupol on Thursday, hitting the fire department's headquarters, a university building and other structures.

AP video captured firefighters rescuing a woman from a destroyed building and trying to save a seriously injured boy.

The city's streets were eerily empty, with most people sheltering indoors. But one man, Aleksander Ivanov, was pulling a trolley with his possessions in search of place to stay because shelling destroyed his home.

At the Brovary Central District Hospital on the eastern outskirts of Kyiv, a 14-year-old girl named Katya lay in bed with the covers pulled up to her neck. She and her father, who was still in surgery, were shot as the family was trying to evacuate.

Katya's mother, identified only as Nina, stood by her side. Her voice caught as she described their ordeal on video.

"From the forest, there came a single shot," she said. "Then we stopped (the car) and then massive shooting began. My husband started to drive fast over the tire spikes in the road. We drove on with flat tires, and my husband was hit in the head and two fingers were blown off. My daughter was shot in the hand."

ARE PEOPLE BEING SAFELY EVACUATED?

Ukrainian President Volodymyr Zelenskyy said 35,000 people managed to evacuate besieged towns and cities on Wednesday, and efforts were underway Thursday to evacuate others in eastern and southern Ukraine, including Mariupol and Kyiv's suburbs.

The Mariupol city council posted a video Thursday showing buses driving down a highway, saying a convoy bringing food and medicine was trying to reach the city and would evacuate civilians during the return leg.

Deputy Prime Minister Iryna Vereshchuk said Thursday that 1,300 civilians have been killed in Mariupol and that Russian forces start shelling the city each time a humanitarian convoy tries to depart for Mariupol to evacuate its residents, though she didn't say whether Thursday's evacuation attempts from the city had failed.

"They want to destroy the people of Mariupol, they want to make them starve," she said. "It's a war crime."

Russian Foreign Minister Sergey Lavrov dismissed concerns about civilian casualties as "pathetic shrieks" from Russia's enemies. He claimed without providing evidence that the Mariupol hospital had been seized by far-right radical fighters who were using it as a base — despite the fact that photos and videos of the aftermath showed pregnant women and children at the site.

WHAT ELSE IS HAPPENING ON THE GROUND?

Russian forces captured several Kyiv suburbs and were trying to take Chernihiv in the north, the general staff of Ukraine's armed forces said Thursday. They were also advancing on the southern cities of Mykolaiv, Kryviy Rih, Voznesensk and Novovorontsovka, it said.

Kyiv Mayor Vitali Klitschko said about 2 million people — half the residents of the Ukrainian capital's metropolitan area — have left the city, which has become a virtual fortress.

"Every street, every house … is being fortified," he said in televised remarks. "Even people who in their lives never intended to change their clothes, now they are in uniform with machine guns in their hands."

Russia has deployed more than 150,000 troops and retains large and possibly decisive advantages in firepower, despite facing fierce Ukrainian resistance and global financial pressure aimed at crippling its economy.

Russia's deputy energy minister, Yevgeny Grabchak, said Thursday that power had been restored to the decommissioned Chernobyl nuclear plant. He said the energy supply came from Belarus, but he didn't elaborate.

WHAT ABOUT DIPLOMATIC EFFORTS?

Several rounds of talks between Ukraine and Russia haven't stopped the fighting, and a meeting Thursday in Turkey between Lavrov and his Ukrainian counterpart, Dmytro Kuleba, failed to find common ground.

In their highest-level talks since the war began, the two sides discussed a 24-hour cease-fire but didn't make progress toward one, Kuleba said. He said Russia was still seeking "surrender from Ukraine."

"This is not what they are going to get," he said, adding that he was willing to continue the dialogue.

Lavrov said Russia was ready for more negotiations but showed no sign of softening Moscow's demands.

Russia has alleged that Western-looking, U.S.-backed Ukraine poses a threat to Russian security. Western officials suspect Russian President Vladimir Putin wants to install a Moscow-friendly government in Kyiv as part of an effort to draw the former Soviet state back into its orbit.

French President Emmanuel Macron joined the ranks of Western leaders who have condemned the Russian airstrike on the Mariupol hospital, calling it "a shameful and amoral act of war."

During a visit to Poland, U.S. Vice President Kamala Harris embraced calls for an international investigation, though she stopped short of directly accusing Russia of having committed war crimes.

WHAT DEFENSIVE ASSISTANCE IS UKRAINE GETTING?

European nations have sent weapons to Ukraine's military. Furthermore, the U.S. House of Representatives passed a bill Wednesday night that would rush $13.6 billion in American aid to Ukraine and its European allies, nearly half of that for sending troops and weapons to Eastern Europe and equipping allied forces there. The bill is expected to pass through the Senate as well in the coming days.

The Ukrainian government says about 20,000 foreigners have joined the so-called the International Legion for the Territorial Defense of Ukraine, where they are given weapons to fight when they arrive. Among them are about 100 of the several thousand Americans who asked to join the fight, a Ukrainian official said.

WHAT'S THE VIEW FROM INSIDE RUSSIA?

During a televised meeting with Kremlin officials on Thursday, Putin addressed the Western sanctions that have caused the ruble to crash and led many major companies to leave Russia.

"The pressure of sanctions has always been there. Yes, of course, now it is complex and creates certain challenges, problems, difficulties for us. But just as we overcame these difficulties in the previous years, we will overcome them now. We must go through this period. The economy will certainly adapt to the new situation."

The list of companies that have stopped operating in Russia grew Thursday to include German fashion brand Hugo Boss, which has temporarily closed its stores, and the U.S.-based Hilton hotel chain, which is closing its corporate office in Moscow and suspending new hotel development in Russia. Hilton's 26 hotels in Russia, which remain open, are owned and operated by franchisees.

Goldman Sachs said it would close its operations in Russia entirely, making it the first major Wall Street bank to do so since Russia invaded Ukraine. Goldman's announcement came after Citigroup said it would start winding down its Russia operations, but that the process would likely take time.

Meanwhile, Twitter launched a privacy-protected version of its site to bypass surveillance and censorship after Russia restricted access to its service in the country. The Kremlin blocked access to Facebook and limited Twitter as part of its broader effort to restrict what Russians can learn about the war. Both companies have said they are working on restoring access to people inside Russia even as they restrict the country's state media from their services.