European Union leaders on Sunday approved a landmark Brexit deal, the basis of Britain's divorce from the 28-member economic bloc, hours after UK Prime Minister Theresa May vowed to campaign with "heart and soul" to get the agreement approved by Parliament amid stiff opposition.

The leaders of the remaining 27 countries of the European Union (EU) signed off on the controversial Brexit withdrawal agreement. European Council President Donald Tusk, after a special summit in Brussels this weekend, tweeted: "EU27 has endorsed the Withdrawal Agreement and Political Declaration on the future EU-UK relations".