The UK Houses of Parliament and the Eiffel Tower in Paris are illuminated in blue and yellow to mark Ukraine's 35th Independence Day.
Night shots show the landmarks glowing in the colours of the Ukrainian flag, with people photographing the Parliament and boats passing along the River Thames.
The displays in London and Paris come as European leaders gather in Kyiv to reaffirm their support for Ukraine.
British Prime Minister Andy Burnham is co-chairing a meeting of the Coalition of the Willing on his first foreign trip since taking office.
His government has also authorised defence firm MBDA to release classified information on British components of the Storm Shadow/SCALP missile, supporting plans to produce the weapon locally in Ukraine.