Macedonia expects 'breakthrough' in Greece talks

Zaev said there was already "an agreement on the principles, and the formal and legal aspect of the agreement."

He did not give details, but the MKD news website reported that the name 'Northern Macedonia' was acceptable to both sides.

The deal is also likely to involve changes to the Macedonian constitution to remove what Greece says are irredentist claims.

Greece has blocked the Former Yugoslav Republic of Macedonia's (its UN designation) progress on the EU and Nato path for decades on grounds that the name Macedonia (its informal title) implied a claim to the Greek region of the same name.

A quick breakthrough could see EU states open accession talks with Macedonia at their June summit and Nato invite it to join at a summit in July.

The deal would then be ratified by Macedonian MPs and by a non-binding referendum, Zaev said.

"We all agree that a referendum will be held in September or October when we expect the citizens to give us directions for our future moves," he said.

Macedonia hopes to be ready to enter the EU in seven to 10 years, providing that the French and Dutch leaders, two enlargement-sceptics, do not block the opening of negotiations in June.

Speaking in Brussels earlier this week, Greek foreign minister Nikos Kotzias also sounded upbeat.

"The documents that have been drafted at a ministerial level will be delivered to the two prime ministers who will discuss between themselves and reach a final deal," he said, after meeting his Macedonian counterpart in the EU capital on Monday.

The EU foreign relations chief, Federica Mogherini, who also spoke to them, said the talks were "extremely encouraging and promising" and that she expected an accord "in the coming days or weeks".

"This will, I believe, have a transformative, powerful effect not only on relations between the two countries, but also on the entire region of the Balkans, and also on Europe," she said.

The breakthrough in the UN-sponsored name talks would help restore faith in the value of diplomacy in turbulent times on the global stage, she added.