LONDON, Feb. 20 (Xinhua) — British Prime Minister David Cameron announced Saturday that his country will hold a referendum on June 23 to decide whether to stay or leave the European Union.

European leaders on Friday night reached a deal on British Prime Minister David Cameron's reforms after marathon talks, President of the European Council Donald Tusk tweeted.

Tusk said on twitter "Deal. Unanimous support for new settlement for UK in EU".

EU heads of state and governments met Thursday and Friday to thrash out a legally binding agreement on EU reforms to keep UK in the 28-nation bloc.

Facing opposition from most member states to his demands on issues such as benefits for EU workers in Britain, British Prime Minister David Cameron's negotiation on reforms to UK's relationship with the EU has dragged out into a marathon battle.