British Prime Minister Theresa May promised EU officials on Tuesday that she would be "a bloody difficult woman" in divorce talks, after being criticized for underestimating the complexity of Brexit talks and having "illusions" over a deal.

Campaigning in the early election she has called for next month, May warned voters that the 27 other EU countries were determined to win a divorce deal that "works for them," saying Britain must unite behind her to strengthen her hand.

"These negotiations will not be easy," she told supporters in the eastern part of the city of Bristol, where voters elected a Labour lawmaker in the last election in 2015.