NATO foreign ministers meet in Brussels on Friday to discuss Russia's invasion of Ukraine as Kyiv called on Western allies to implement a no-fly zone or provide them with more planes to protect civilians and infrastructure including nuclear plants.

Ukrainian President Volodymyr Zelenskiy has consistently called for a no-fly zone since Moscow's invasion more than a week ago, but NATO allies have resisted a step that could drag them into the war with nuclear-armed Russia.

Speaking ahead of the meeting in NATO's Brussels headquarters, Lithuania said the alliance would be dragged into the war if it were to enforce a no-fly zone.

"All encouragements for NATO to get involved into the military conflict now are irresponsible," said Lithuanian Prime Minister Ingrida Simonyte.

Canadian Foreign Minister Melanie Joly said that NATO's red line was to avoid triggering a wider international conflict, but said all scenarios should be discussed.

France's presidential office described a no-fly zone as "a very legitimate request and very difficult to satisfy."

On Thursday Zelenskiy said that if allies wouldn't meet his request to protect Ukrainian air space, they should instead provide Kyiv with more war planes.

While Russian President Vladimir Putin's land assault on the capital Kyiv has stalled, Russian forces have shelled residential blocks and key civilian infrastructure, including in Ukraine's second-largest city of Kharkiv in the northeast.

Ukraine said on Friday that Russian forces seized the largest nuclear power plant in Europe after a building at the complex - but not the reactor - was set ablaze during intense fighting near the southern city of Zaporizhzhia.

The fire was later extinguished.

The Azov Sea port of Mariupol has been encircled and left without electricity or running water by heavy Russian bombing, Ukrainian officials said.

(Writing by Gabriela Baczynska; Editing by Frank Jack Daniel)