British Foreign Secretary David Cameron held a meeting in Florida with Donald Trump, with whom he has clashed in the past over Brexit and NATO, as the U.K. tries to persuade the presidential candidate’s Republican allies to stop obstructing a commitment to send more U.S. aid to Ukraine.

Their talks late Monday came ahead of Cameron’s trip to Washington to meet Republican lawmakers as well as officials from the administration of U.S. President Joe Biden.

The visit comes at a sensitive time as the U.K., France and other nations try to keep the international focus on Ukraine’s battle to repel Russia’s invasion.