Mexico’s president, Andrés Manuel López Obrador, said on Saturday he would not congratulate a winner of the US presidential election until legal challenges are concluded, in an apparent bid to avoid friction with Washington during the transition.

Democrat Joe Biden won the election on Saturday after a victory in the battleground state of Pennsylvania put him over the threshold of 270 electoral college votes.

Mexico is the United States’ top trade partner, with over $600bn of annual two-way commerce, and the bilateral relationship with its northern neighbour is by far the most important for Mexico.

“With regard to the US election, we are going to wait until all the legal matters have been resolved,” López Obrador, commonly known as Amlo, said at a news conference.

“I can’t congratulate one