Lawmakers in Bulgaria have voted to lift nationalist Ataka party leader Volen Siderov and Ataka MP Desislav Chukolov's immunity from criminal prosecution.

The step was requested by Chief Prosecutor Sotir Tsatsarov on two counts of hooliganism in October.

Excluding Ataka party itself, MPs approved the waiver almost unanimously, with 144 of them voting "for", 11 (Ataka members) against and one, from the opposition Bulgarian Socialist Party (BSP) choosing to abstain.

Under Bulgarian law, a lawmaker's immunity can only be sought - and lifted - over a particular offense. Requests submitted by the prosecution can only refer to a specific case, and another violation has to be addressed separately.

Parliament's decision follows a move by an ad hoc committee set up by lawmakers who also voted "yes" at a Tuesday meeting.

The development comes as Tsatsarov's request prompted the legislature to start discussions on constitutional changes that might bring about a change to immunity rules.