MEXICO CITY (Reuters) - Mexico’s ambassador to the United States on Tuesday called Joe Biden the “prospective” President-elect, in what could indicate a slight shift in position after the Mexican government said it was too soon to recognize a winner of the U.S. election.Ambassador Martha Barcena published a series of talking points on Twitter titled “Position of the Government of Mexico” containing the new language. It was not immediately clear if the choice of words signalled a shift in Mexico’s official stance. The Democrat former vice president secured the presidency by winning Pennsylvania on Saturday, but Republican President Donald Trump has so far refused to concede, and is pursuing lawsuits in several states in a bid to hold on to power citing “illegal” ballots. State officials have said there were no significant irregularities in the Nov. 3 election. The Mexican foreign ministry did not offer specific comments on the ambassador’s statement, with a ministry official saying it had been issued by the embassy.