BELGRADE, Serbia — Unesco, the United Nations’ cultural agency, narrowly denied Kosovo membership on Monday, handing a sizable political victory to Serbia, which had fought a fierce battle against the bid for months.

Kosovo’s candidacy was supported by the major Western countries and was seen as a strategic step toward United Nations membership and full international recognition for the former Serbian province, which separated in 1999 after an American-backed NATO bombing campaign that drove out Yugoslav forces.

A majority of members at the agency’s general conference in Paris voted for Kosovo’s membership — 92 to 50, with 29 abstentions. But Unesco rules require a two-thirds majority to accept a new member state.

“I congratulate the citizens of Serbia who have had the confidence to defend that which our ancestors have preserved for centuries,” President Tomislav Nikolic of Serbia said in a statement. “This is a just and moral victory under almost impossible conditions.”