The leaders of Britain and France are spearheading a desperate diplomatic drive to shore up Europe's security, bolster Ukraine's defenses and ensure the Trump administration doesn't seek a ceasefire on terms that reward Moscow for invading its neighbor.

UK Prime Minister Keir Starmer on Sunday said he does not accept that United States under President Donald Trump was an unreliable ally, but stressed that Europe must continue to fund Ukraine to back it amid the ongoing war with Russia.