Hundreds of pro-Russian Serb nationalists have held a protest against government's deal that forges closer ties with NATO.

The protesters on Saturday in downtown Belgrade chanted slogans against the Western military alliance, Serbia's leaders and carried portraits of Russian President Vladimir Putin while waving Russian flags.

Serbia has historic ties with Slavic ally Russia but was never part of the Soviet bloc and wants to join the European Union.

The right-wing nationalists want Serbia never to be part of NATO, which bombed the country in 1999 over its former regime's bloody crackdown against Kosovo Albanian separatists.

The Kremlin and its media outlets in the Balkan country have launched an anti-Western campaign, including denouncing a recent government agreement with NATO to allow its troops patrolling Kosovo unhindered passage through Serbia.