London, Mar 29 (IANS): British Prime Minister Theresa May made telephone calls late Tuesday to German Chancellor Angela Merkel, European Council President Donald Tusk and European Commission President Jean-Claude Juncker, Downing Street said.

A Downing Street spokesperson said the phone calls were aimed to "update them ahead of the letter giving notification of the UK's intention to withdraw from the European Union being delivered tomorrow (Wednesday).

"In separate calls, they agreed that a strong EU was in everyone's interests and that the UK would remain a close and committed ally.

"They also agreed on the importance of entering into negotiations in a constructive and positive spirit, and of ensuring a smooth and orderly exit process," the spokesperson said.

After the phone calls, May signed the Article 50 notification letter which will officially begin Britain's exit from the European Union (EU), local media said.

May will officially trigger Article 50 in the letter that will be hand delivered to Tusk at 1:30 p.m. Brussels time on Wednesday, the BBC reported.