A Muslim suicide bomber killed at least four people Tuesday morning at the Russian-Backed parliament in Chechnya, where Muslim insurgents are challenging Moscow. Hostages were taken, but one Russian source said that all of the terrorists have been killed or arrested.

The suicide bomber detonated the explosives outside the parliament building, and two others fought a gun battle with guards in the office of the speaker of the parliament, according to Russian news agencies. Three guards, a civilian and three terrorists, including the suicide bomber, were killed.

“A vehicle carrying terrorists drove in with cars carrying lawmakers. One of them blew himself up and the others headed toward parliament,” a police source told RIA Novosti.

Three months ago, a suicide squad staged a massive attack on the home village of Chechen leader Ramzan Kadyrov, a former rebel who became an ally of the Kremlin. Growing Muslim insurgency in the region has challenged the government and Russia in an area near Russia’s southern border, populated mostly by Orthodox Christians.

Moscow previously has declared it has defeated Chechen separatists, but recent bombings and other attacks indicate the insurgents have not surrendered. Radical Islam has leaned on poverty and local corruption to build opposition to authorities.

Chechnya is almost completely surrounded by Russian territory.