European Union Council President Donald Tusk said on Friday an agreement to keep Britain in the bloc won unanimous support from all of the EU states 28 leaders.
"Deal. Unanimous support for new settlement for #UKinEU," Tusk wrote on Twitter.
UK Prime Minister David Cameron tweeted he had negotiated a deal that he would recommend to his cabinet on Saturday.
EU leaders said the two sides had reached agreement on a package of measures to reform Britain's ties with the European Union at a summit in Brussels.
Earlier Lithuanian President Dalia Grybauskaitė had tweeted a deal had been done with with the UK to remain in the European Union.
Reuters reported it has been the EU-UK accord with showed the "emergency brake" on in-work benefits for migrants will not be extendable beyond seven years.
The European heads of state and government have taken a break from the negotiations to dine during the second day of the summit.
Czech Prime Minister Bohuslav Sobotka says the deal is a "decent compromise".
