A U.N. negotiator has arrived in Macedonia for talks with the country's leadership, in a revived effort to settle a peculiar but acrimonious dispute with neighboring Greece over Macedonia's name.

Matthew Nimetz, who has already met with Greek officials in Athens, says there appears to be momentum for solving the dispute that has poisoned the two countries' relations since Macedonia won independence from the former Yugoslavia in 1991.

On Thursday, Nimetz will meet Macedonia's president, government officials and opposition leaders.

The dispute has frozen Macedonia's NATO accession hopes, as Greece, an alliance member, refuses to endorse its bid until a solution is found.

Greece says the country's name implies claims on its own adjoining province of Macedonia and wants its neighbor to amend its name, adding a modifier like 'New' or 'North'. Skopje denies it has any territorial claims on its neighbors.

Opponents of a compromise deal are organizing a rally Sunday in Athens, backed by the Greek Orthodox Church.