The war has forced more than 2.3 million people to flee the country as others try to seek refuge in basements, subway stations and underground shelters.

Ukraine's president said 100,000 people were evacuated over the past two days in the north and center of the country. Humanitarian corridors to facilitate the exodus were agreed to by Russia and Ukraine during ceasefires in those areas.

More evacuations are expected Friday, though repeated attempts to reach the besieged city of Mariupol in the south have failed under continued Russian shelling.

On Friday, Russia appeared to be pushing its offensive westward with authorities in Ukraine saying airstrikes hit two cities that had been far from Russia's main targets elsewhere, indicating a potentially new direction for the war.

Western nations have been largely united around ways to punish Russia economically. U.S. President Joe Biden is expected to announce Friday an agreement with other nations to revoke Russia's "most favored nation'' trade status, allowing for tariffs to be imposed on Russian imports.

The U.S. Congress late Thursday approved a $13.6 billion emergency package of aid for Ukraine and its European allies. Much of that will go toward arming and equipping Ukraine's military, as well as for humanitarian and economic assistance.

Here are some key things to know about the war:

WHAT HAS THE AP DIRECTLY WITNESSED OR CONFIRMED?

Nighttime temperatures in the southern port city of Mariupol are regularly below freezing, and daytime ones normally hover just above it. The city of 430,000 has been without food supplies, running water and electricity for 10 days.

Some 1,300 civilians have been killed in Mariupol throughout the siege, according to Ukrainian Deputy Prime Minister Iryna Vereshchuk. It was not possible to independently verify the figure.

On the outskirts of the capital, Kyiv, AP reporters witnessed a teenage girl recovering at a hospital after her family was ambushed as they tried to flee the area. She was shot in the hand when their car was raked with gunfire from a roadside forest, her mother said. The girl's father underwent surgery after being shot while driving frantically from the ambush.

WHAT ELSE IS HAPPENING ON THE GROUND?

Russian airstrikes hit near airports in the western cities of Ivano-Frankiivsk and Lutsk. The two cities are far from Russia's main attack targets elsewhere in Ukraine. There were no immediate reports of casualties.

Russia said it used high-precision long-range weapons Friday to put military airfields in the two cities ``out of action.''

Russia's Defense Ministry also said Friday that an offensive, led by fighters from the separatist-held Donetsk region, are further squeezing the city of Mariupol.

Russian forces continued their offensive toward the capital, Kyiv, on Friday, trying to break through Ukrainian defenses to the northwest, the general staff of Ukraine's armed forces said in a statement.

Satellite images show a huge Russian convoy that had been mired outside the capital, Kyiv, has fanned out into towns and forests. The immediacy of the threat to Kyiv was unclear.

Three more Russian airstrikes hit the industrial city of Dnipro in eastern Ukraine on Friday, killing at least one person, according to the Ukrainian interior ministry. The city is home to nearly 1 million people.

WHO ARE THE "VOLUNTEER'' FIGHTERS IN THIS WAR?

Russian President Vladimir Putin on Friday approved bringing "volunteer'' fighters from around the world to join Russia's Ukraine offensive. Russia's defense minister said there had been ``more than 16,000 applications'' from countries in the Middle East, many of them from people who he said fought alongside Russia against the Islamic State group.

Already, the Ukrainian government says about 20,000 foreigners have joined the so-called International Legion for the Territorial Defense of Ukraine to fight the Russians.

The pro-Ukrainian fighters are given weapons when they arrive. Among them are about 100 of the several thousand Americans who asked to join the fight. A lawmaker in Canada says about 1,000 Canadians have applied to fight for Ukraine.

ARE PEOPLE BEING SAFELY EVACUATED?

Ukrainian authorities said there are plans, with support from the Red Cross, for several evacuation and humanitarian aid delivery routes Friday. The top priority remains to free people from the city of Mariupol and getting aid to its desperate population.

Buses are being sent Friday to multiple Kyiv suburbs to bring people to the capital, where authorities say half of the metropolitan area's population, or around 2 million, has already fled.

There are also efforts to create new humanitarian corridors around the cities of Kherson in the south, Chernihiv in the north and Kharkiv in the east. Russian forces are blockading Kharkiv and pushing their offensive in the south around three cities and towns, including Ukraine's president hometown of Kryvyi Rih.

WHAT ABOUT RUSSIA'S CLAIMS THAT BIOWEAPONS ARE BEING DEVELOPED IN UKRAINE?

The U.N. Security Council will meet on Friday to discuss Russia's claims that the United States is conducting "military biological activities'' in Ukraine.

In response to the Russian accusations, White House press secretary Jen Psaki warned this week that Russia might use chemical or biological weapons against Ukraine. She also described Russia's claim as "preposterous.''

WHAT'S THE VIEW FROM INSIDE RUSSIA?

During a televised meeting with Kremlin officials on Thursday, Russian President Vladimir Putin said his country's economy "will certain adapt'' to Western sanctions that have caused the ruble to crash and led many major companies to leave Russia.

The list of companies that have stopped operating in Russia continues to grow with each day. The list includes fashion retailers, car manufacturers, hotel chains, food outlets and investment banks.

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.