A barrage of deadly missile strikes on Tuesday hit residential buildings in Ukraine's capital Kyiv and the northeastern city of Kharkiv with five dead and dozens of civilians wounded.

On Wednesday, Poland's top diplomat Radoslaw Sikorski said on social media that the West should respond "in language that Putin understands".

He urged allies to provide Kyiv with "long-range missiles that will enable it to take out launch sites and command centres".

Poland is among Ukraine's staunchest allies, with the new administration in Warsaw doubling down on political support to the neighbouring country.

Sikorski also said the response to Russia pummelling Ukraine should include "tightening" of Western sanctions against Moscow so that it "cannot make new weapons with smuggled components".

Appointed in December as Poland's foreign minister in the new pro-EU government, Sikorski chose Ukraine for his first visit abroad, where he said the West should "mobilise" its economy to arm Ukraine.