Here are the latest developments in the war in Ukraine:

- Ukraine rejects neutrality -

Ukraine rejects proposals put forward by Russia during peace talks for it to become neutral, like Austria or Sweden.

A Ukrainian negotiator stressed the country was at war with Russia and called on Ukraine's allies to underwrite its security.

In the past 48 hours, Ukrainian officials have sounded more positive about the chances of a peace deal while warning that significant differences remain.

- Zelensky to address Congress -

Ukrainian President Volodymyr Zelensky is expected to appeal to NATO to ramp up pressure on Russia during a landmark speech to the US Congress by video link.

Zelensky could repeat his calls for the imposition of a no-fly zone over his country. US President Joe Biden is set to announce $800 million in new security assistance to Ukraine.

- Explosions in central Kyiv -

Explosions rock central Kyiv as Russia intensifies its attack on the capital, which is under a 35-hour curfew due to what its mayor called a "difficult and dangerous moment".

Two residential buildings were damaged and two people wounded, emergency services say.

- Strikes on train station -

Russian strikes also target the southern city of Zaporizhzhia, where thousands of people are taking shelter after escaping the besieged port of Mariupol, regional officials say.

The railway station is hit but there are no reports of casualties.

- European leaders return -

A trio of leaders from Poland, the Czech Republic and Slovenia, who braved bombardments to travel to Kyiv to meet Zelensky, arrive back in Poland.

During the visit, Poland called for NATO peacekeepers to be deployed in Ukraine.

- News sites blocked -

Russia's media regulator blocks access to at least a dozen news sites, ramping up a crackdown on the media launched after the start of the war.

Those affected include the award-winning investigative website Bellingcat and regional site Permdaily.ru. The move comes two days after a Russian journalist staged an anti-war protest during a prime-time news broadcast on Russian state television.

- Payment day for Russia -

Russia is due to make an interest payment on its foreign debt as Western sanctions over the Ukraine conflict have raised concerns that Moscow could default.

Moscow is due to pay $117 million (107 million euros) on two dollar-denominated bonds. It says it will service its debt in rubles.

- Five journalists killed -

A French-Irish cameraman for Fox News and a Ukrainian working as a producer for the US television network have been killed in fighting near Kyiv, Fox News says.

Two other Ukrainian journalists, as well as a US documentary filmmaker, have also been killed.

- 20,000 leave besieged city -

Around 20,000 people manage to leave the besieged port city of Mariupol by driving along a humanitarian corridor agreed with Russian forces, a Ukrainian presidential aide says.

- Refugees top 3 million -

More than three million people have fled Ukraine since the start of the military operation, the UN migration agency IOM says.

Around half are minors, says the UN children's agency.

The UN refugee agency, UNHCR, says 1.8 million people have fled to Poland.

- 97 children killed -

Ninety-seven Ukrainian children have died since the military operation began, Zelensky tells Canadian lawmakers.

He renews his calls for a no-fly zone over Ukraine to "stop the bombing."

NATO allies, including Canada, have rejected the proposal, fearing it would lead to an expansion of the conflict.