Macedonia's parliament on Monday ratified a landmark friendship pact with Balkan neighbor Bulgaria designed to dampen a historic rivalry in a region beset by old ethnic and territorial disputes.

Under the treaty, both countries have renounced territorial claims against each other, and Bulgaria has committed to back Macedonia's bids to join the European Union and NATO.

The deal also calls for a committee to "objectively" re-examine common history, which could lead to a review of school textbooks.

Lawmakers backed the agreement though the majority in favor was accentuated by the fact that Macedonia's main conservative opposition party, VMRO-DPMNE, boycotting the session as part of a protest over the arrest of six of its lawmakers for alleged involvement in a parliament invasion last year.

VMRO-DPMNE opposed the ratification, saying the pact contains "serious faults" and fails to recognize the existence of a Macedonian ethnic minority in Bulgaria.

A party statement also complained that the potential school textbook review "is beyond common sense and the principles of science."

Bulgaria has already ratified the pact.