Ukraine and Russia: What you need to know right now

UKRAINE'S military said the public should brace for more indiscriminate Russian shelling of critical infrastructure, as U.S. President Joe Biden issued one of his strongest warnings yet that Moscow is considering using chemical weapons.

Russia's almost month-old assault on Ukraine has stalled along most fronts, failing to seize any major city or topple the government. But shelling and missiles are causing devastation.

FIGHTING

* The focal point is Mariupol, a strategically important southern port. There, horror and bewilderment stalk the devastated, Russian-besieged city, where some bury neighbours in roadside graves.

* Russian artillery continues to pound the eastern cities of Kharkhiv, Sumy and Chernihiv.

* In the capital Kyiv, shells hit a shopping centre on Sunday evening, killing at least eight people.

REFUGEES

* Nearly 6.5 million people have been uprooted from homes, the United Nations says. Just over 8,000 people were evacuated on Monday.

SANCTIONS

* The European Union cannot agree on whether or how to impose sanctions on Russia's lucrative energy sector. Germany says the bloc is too dependent on Russian oil for that.

DIPLOMACY

* Peace talks resumed but there is no sign of significant progress.

* Ukrainian President Volodymyr Zelenskiy said it would not be possible to negotiate an end to the war without meeting Kremlin leader Vladimir Putin.

* U.S.-Russia bilateral ties were on the brink of collapse, Russia's foreign ministry said, summoning the U.S. ambassador after Biden called Putin a "war criminal."

READ MORE: Latest development on Ukraine-Russia crisis

COMING UP

* The U.N. General Assembly is expected to vote again this week on a motion criticising Russia for the humanitarian crisis in Ukraine.

QUOTES

* "Please think about how many things he has come through," President Volodymyr Zelenskiy said, referring to Boris Romanchenko, a 96-year-old Holocaust survivor who was killed last week when shelling hit his flat in Kharkiv.

* "Everything is destroyed. Where can we go?" asked librarian Irina Chernenko in a dark cellar in Mariupol packed with families for 11 days.