BRUSSELS (Reuters) - Serbia and Kosovo have reached a deal to allow politicians from Belgrade to campaign during a Kosovo municipal election on November 3, smoothing over a row that had underscored the fragility of relations between the two.

Last week, Serbia's prime minister threatened to pull out of talks with Kosovo - mediated by the European Union and intended to improve relations between Belgrade and Pristina over the long-term - after the former Serbian province denied him permission to visit.

After a late-night meeting in Brussels on Monday, Ivica Dacic said the issue was resolved.

"My credibility was called into question because I couldn't go to Kosovo. That was not sustainable, it was clear to everyone," he told reporters in Brussels.

Serbia and Kosovo, which seceded in 2008 in the last act in the break-up of former Yugoslavia, signed a landmark deal in April, agreeing for Belgrade to renounce its de facto hold over a small Serb-populated pocket of majority-Albanian Kosovo. Implementation of a number of issues remains open.

In part as a reward for the deal, the European Union is expected to open accession talks with Serbia in the coming months.

Under the April deal, the northern Serb pocket is slated to take part in a Kosovo municipal election on November 3.

Dacic had planned to visit minority Kosovo Serbs to encourage them to take part in the vote, but the government in Pristina said he would be denied access for the duration of the election campaign.

NATO waged an air war to drive Serbian forces out of Kosovo in 1999 and stop ethnic cleansing after negotiations failed to halt a conflict that was destabilizing the Western Balkans.

(Additional reporting by Aleksandar Vasovic in Belgrade and Clement Rossignol in Brussels; Editing by Sandra Maler)