Kosovo police say that the public broadcaster's building has been attacked with a hand grenade that caused material damage.

A statement Tuesday said the grenade was thrown at the yard of the Kosovo Radio and Television headquarters in the capital, Pristina last night. No one was injured in the attack.

The attack has been condemned by the government, all political parties and the international community as an attack against freedom of speech.

The blast comes amid political tensions over a border demarcation deal with Montenegro and a separate agreement with Serbia that gives more powers to ethnic Serbs in Kosovo.

The opposition has disrupted parliament's work with tear gas canisters and other violence and its supporters have clashed with police outside in an attempt to scupper the deal.