The humanitarian situation in the country's besieged cities grew more dire, including in Mariupol, where bodies lay uncollected in the streets and hopes for a mass evacuation of civilians were dashed again.
A Ukrainian military official said the country needs air-defense systems most of all.
Satellite photos from Planet Labs PBC show a buildup of Belarussian and suspected Russian helicopters at Machulishchy Air Base outside Minsk, Belarus, on Tuesday. And analysts believe flooding north of Kyiv seen in satellite photos likely comes from Ukrainian forces trying to stop the Russian advance.
Here's a look at key things to know about the war:
WHAT HAS BEEN DIRECTLY WITNESSED OR CONFIRMED BY THE ASSOCIATED PRESS?
Women and children in Mariupol gathered in a basement shelter as outgoing artillery fire blazed in the distance. One of the women, Goma Janna, lamented, ``Why shouldn't I cry? I want my home, I want my job. I'm so sad about people and about the city, the children.''
Civilians in Mariupol, a city of roughly 430,000 people, have been without water, heat, sanitary systems and phone service for several days, and many have turned to breaking into shops. A video showed a Ukrainian soldier telling people, ``People, please be united. You don't need to panic. Please don't steal everything. You will live here together.''
Videos showed people boarding buses in Sumy on Tuesday and buses marked with a red cross driving along a snowy road as they headed out of the city. Ukrainian Deputy Prime Minister Iryna Vereshchuk said both sides agreed to a cease-fire from 9 a.m. to 9 p.m. for the evacuation of Sumy civilians, who were headed southwest to the Ukrainian city of Poltava.
HOW ARE EVACUATIONS GOING?
Vereshchuk said 5,000 people were evacuated from Sumy. The Russian military gave a different number, saying 723 people were evacuated from the city and identifying them as mostly citizens of India, with the rest from China, Jordan and Tunisia. It made no mention of Ukrainians among the evacuees.
But the planned evacuation of civilians from Mariupol failed because Russian troops fired on a Ukrainian convoy carrying humanitarian cargo to the city that was later going to ferry people out, Vereshchuk said.
Natalia Mudrenko, an official with Ukraine's U.N. mission, accused Russia of effectively holding civilians ``hostage'' and said ``the critical situation'' in Mariupol and other cities demands immediate action by world leaders and humanitarian and medical organizations.
She told a U.N. Security Council meeting Tuesday afternoon that civilians, mostly women and children, ``are not allowed to leave and the humanitarian aid is not let in.''
The Russian military has denied firing on convoys and accused Ukraine of blocking the evacuation effort.
Repeated attempts to create safe evacuation corridors have failed since last weekend amid continuing fighting and objections to the proposed routes.
WHAT ELSE IS HAPPENING ON THE GROUND?
Russian aircraft on Tuesday night bombed residential areas around Kharkiv, Ukraine's second-largest city, and Zhytomyr, to the west of Kyiv, and its military also stepped up its shelling of Kyiv's suburbs, the Ukrainian emergency services said.
In Malyn, a town of 25,000 near Zhytomyr, the bombing killed at least five people, including two children, and destroyed a textile factory and seven homes, the agency said. Two people died, including a 7-year-old, in the bombing in Chuhuiv, near Kharkiv.
Ukrainian officials also reported dire conditions in the Kyiv suburbs of Bucha, Hostomel, Irpen, Vyshhorod and Borodianka, including bodies of the dead that couldn't be buried.
The mayor of Lviv said the city in far western Ukraine was struggling to feed and house the more than 200,000 people who have fled there. The displaced are being housed in the city's sport halls, schools and other buildings.
In the nearly two weeks since Russian President Vladimir Putin launched the invasion, his forces have captured a swath of southern and coastal Ukraine but have seen their advances stopped in many areas, including around Kyiv.
Ukrainian President Volodymyr Zelenskyy vowed that his country would fight Russia's invasion in its cities, fields and riverbanks.
``We will not give up and we will not lose,'' he told Britain's House of Commons via video, evoking the ``never surrender'' speech that Winston Churchill gave during World War II.
HOW MANY PEOPLE HAVE BEEN KILLED?
Thousands of people are thought to have been killed, both civilians and soldiers, though the actual number is unknown.
The U.S. believes Russia underestimated the strength of Ukraine's resistance before launching its invasion and has suffered thousands of casualties, Director of National Intelligence Avril Haines told lawmakers Tuesday in Washington.
WHAT ABOUT AID TO UKRAINE?
Additional air-defense capabilities are the No. 1 priority for Ukraine, Maj. Gen. Borys Kremenetskyi, the defense attache with the Ukrainian Embassy in Washington, said Tuesday after visiting the Pentagon.
``It can be ground-based air-defense systems. It can be fighter jets, whatever possible,'' Kremenetskyi told The Associated Press.
He said there are countries around the world that have Soviet-produced air-defense systems that the Ukrainians know how to operate.
``The U.S. government can also motivate those countries to provide us this equipment,'' he said.
Poland said Tuesday that it would give all of its MiG-29 fighter jets to the U.S., which Ukrainian pilots are trained to fly. But the Pentagon responded that Poland's offer to give the jets to the U.S. so they can be passed to Ukraine is not tenable and raises serious concerns for the NATO alliance.
Pentagon spokesman John Kirby said the U.S. will continue to talk to Poland about the matter.
HAVE SANCTIONS AGAINST RUSSIA BEEN RATCHETED UP?
Yes. U.S. President Joe Biden said the U.S. would ban all Russian oil imports, even if it will mean rising costs for Americans, particularly at the gas pump. Energy exports have kept a steady stream of cash flowing to Russia despite otherwise severe restrictions it faces.
Russia's Central Bank sharply tightened currency restrictions in ways not seen since Soviet times. It ordered the country's commercial banks to cap the amount clients can withdraw from their hard currency deposits at $10,000 in U.S. dollars. Any withdrawals above that amount would be converted to rubles at the current exchange rates.
Surging prices for oil and other vital commodities, such as wheat used in government- subsidized bread and noodles, are rattling global markets.
McDonald's, Starbucks, Coca-Cola, PepsiCo and General Electric all announced Tuesday they're temporarily suspending business in Russia. Shell said Tuesday it will stop buying Russian oil after Ukrainian officials criticized the energy giant for buying a shipment of crude from Moscow.
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