Tensions between Ukraine and Russia are escalating after Ukraine fired UK-made cruise missiles at Russia for the first time in the 1,000 day conflict.

According to international media reports, the attack on Russian targets with Storm Shadow missiles follows a strike on Tuesday by Ukraine with US-supplied ATACMS missiles in the Bryansk region.

According to reports by Bloomberg and the Guardian, among others, earlier on Wednesday, the UK approved the missile hits after Russia deployed North Korean troops to its border with Ukraine.

UK and US officials view the move as a major escalation in the conflict.

Earlier on Wednesday, the US closed its embassy in Kyiv for fear of a potential Russian air attack. Italian and Greek embassies also closed.

Meanwhile, in the midst of intensifying conflict, Reuters reports that Russian President Vladimir Putin may be open to discussing the possibility of a ceasefire with US President-elect Donald Trump.

Earlier, Putin had warned that strikes in Russian territory with US- and UK-made missiles could trigger a direct war between Russia and NATO countries. He approved lowering the threshold for Moscow to bring nuclear weapons into the conflict as a response to enemy attacks with conventional weapons.

Commenting on the news on Wednesday, Turkish President Tayyip Erdogan said a U.S. decision to allow Ukraine to use long-range missiles to attack Russian territory would “further enflame the war and ensure that it never ends but spreads”.