KYIV: Here are the latest developments in the war in Ukraine:

100,000 trapped in Mariupol

Ukrainian President Volodymyr Zelensky says almost 100,000 people are still trapped in the ruins of Mariupol, though over 7,000 escaped in the last 24 hours.

Human Rights Watch describes the southern city as a "freezing hellscape riddled with dead bodies and destroyed buildings".

The Pentagon says Russia is pummelling the city using artillery and long-range missiles and from naval ships deployed in the nearby Sea of Azov.

Ukraine forces on offensive

For the first time, there are signs that Ukrainian forces are going on the offensive, retaking a town near Kyiv and attacking Russian forces in the south of the country.

"We're definitely seeing anecdotal evidence... that the Ukrainians are not only defending well, where they choose to defend, but they are making efforts to take back territory," a senior US defence official tells journalists.

Russian army 'struggling': US

The Pentagon says Russian forces "have struggled with logistics and sustainment."

"We think they're having command and control problems," adds Pentagon spokesman John Kirby.

A senior defence official says the Pentagon believes as much as 10 percent of Russian forces committed to Ukraine may have been knocked out in just four weeks of fighting.

Ukraine's army command says it believes Russian troops now have sufficient ammunition, food and fuel for just three days.

UN slams 'absurd war'

UN chief Antonio Guterres calls on Russia to end its "absurd war" in Ukraine, calling the conflict "unwinnable".

The UN General Assembly is due to reconvene a special emergency session on Ukraine on Wednesday and vote this week on a non-binding French and Mexican resolution condemning Russia's invasion.

Nuclear option

Russia would use nuclear weapons in the context of the Ukraine conflict if it were facing an "existential threat," Kremlin spokesman Dmitry Peskov says in a CNN interview.

The comments came when he was asked if he was "convinced or confident" that President Vladimir Putin would not use the nuclear option in the Ukrainian context.

Navalny sentenced to nine years

Jailed Kremlin critic Alexei Navalny is found guilty of additional charges and his sentence is extended to nine years as Moscow stamps out dissent.

Navalny, who will serve his new sentence in a strict penal colony with harsher conditions, urged Russians to resist "these war criminals."

Russia seeks 'substantial' talks

Russia says it wants peace talks with Ukraine to be "more substantial" after several rounds of inconclusive negotiations.

Zelensky renews his call for direct talks with his Russian counterpart Putin.

Zelensky seeks papal mediation

Zelensky speaks with Pope Francis, urging him to mediate in the country's conflict and inviting him to visit Ukraine.

The Pope has previously called for an end to the "massacre" in Ukraine, saying the "unacceptable armed aggression" must be stopped.

New Western sanctions

More sanctions against Russia and the tightening of existing measures will be announced Thursday when President Joe Biden meets European allies in Brussels, US officials say.

Biden will attend summits with NATO, the G7 group and the European Council on Thursday before flying Friday to Poland for meetings there.

Separately, the US says it has seen no evidence so far of recent Chinese weapons shipments to Russia despite Moscow's request to Beijing for assistance.

Zelensky addresses

Zelensky urges Italian lawmakers to stop their country from being a playground for Russia's elite, and warns food shortages caused by the war could risk a new migrant crisis.

Zelensky is due to address Japan's Diet and the French parliament later in the day, and has been invited to speak Thursday to the NATO summit via videolink.

'False news' law

Alexander Nevzorov becomes the first prominent political reporter and commentator to be probed for spreading "false" information about the Russian army under new legislation introduced after the invasion.

Over 3.5 million flee

Over 3.5 million Ukrainians have now fled the country following Russia's invasion, the United Nations says. More than 10 million have been displaced from their homes.