MOSCOW — Heavily armed gunmen burst into the Parliament building of Chechnya, in southern Russia, on Tuesday morning, killing at least three people and wounding more than a dozen before the assailants were killed by police officers or by their own explosives, officials said.

The assailants, including one suicide bomber, sprayed automatic rifle fire and set off at least one explosion in one of the most brazen assaults to occur for some time in Chechnya, a region in the volatile North Caucasus where violence linked to a simmering Islamist insurgency is common.

The police prevented the militants from reaching Parliament members’ chambers, investigators said, though the men were able to barricade themselves on the first floor and open fire.

Investigators said three gunmen drove through the front gates of the Parliament complex, in a busy section of downtown Grozny, Chechnya’s capital. Without uttering a word they killed two police officers standing guard at the entrance, said Alvi A. Karimov, the press secretary for Ramzan A. Kadyrov, Chechnya’s leader. One militant then blew himself up, killing a staff member, Karimov said. The blast blew out windows and wounded several others.

Russian television showed panicked workers, some with wounds, stumbling past corpses to flee the Parliament grounds, while heavily armored police officers in helmets and bulletproof jackets raced in.

Parliament members were evacuated, though at least 17 people, including six police officers, were wounded in the attack, which ended when special forces units killed the remaining militants.