VIENNA (Reuters) - Macedonia expects to reach a settlement of its decades-old name row with Greece by a NATO summit in the summer, its prime minister said on Monday.

The two countries have agreed to step up negotiations this year to resolve the dispute, which has frustrated the ambitions of Greece’s small northern neighbor to join NATO and the European Union. Greece is a member of both.

Greece objects to the former Yugoslav republic’s use of the name Macedonia, arguing that it, along with contentious articles in Skopje’s constitution, could imply territorial claims over its own northern region of the same name.

The foreign ministers of the two countries met the United Nation’s special envoy Matthew Nimetz in Vienna earlier this month to discuss the issue.

“I believe we will be able to conclude the negotiations successfully by the NATO summit in July,” Macedonian Prime Minister Zoran Zaev, who took over last May and pledged to work closer with Greece, said in an interview with Austrian radio station ORF.

Talks between the two states have been inconclusive since 1991, when Macedonia withdrew from former Yugoslavia. It was admitted into the United Nations in 1993 under the name Former Yugoslav Republic of Macedonia (FYROM).

Macedonia said earlier this month it was ready to add a geographical qualifier to its name to help resolve the dispute with Greece, in an effort to increase its prospects of joining the European Union and NATO.

“We have an automatic invitation, meaning NATO members will start ratifying our (NATO) accession as soon as we and Greece announce that the problem has been solved,” Zaev said.

The NATO summit will be held on 11 and 12 July in Brussels.