Philip Hammond, speaking in Switzerland ahead of Trump's inauguration Friday, said "the change of administration in Washington is a very big issue" for Britain and the rest of the EU.
After a campaign critical of free trade and Europe's migration and defense policy, Trump "has probably introduced a bigger uncertainty" for the EU than the Brexit vote, Hammond said, AP reported.
Barclays CEO Jes Staley, speaking with Hammond at the World Economic Forum, said the US vote for Trump "clearly challenged the notion of a global economic union" and urged the new Trump administration not to attack free trade.