Four militants allegedly planning a series of terrorist attacks in the republic of Chechnya have been killed in a counterterrorism raid, Russia’s National Antiterrorism Committee (NAC) said Tuesday.

The counterterrorism operation in the Chechen capital of Grozny was ordered by regional Federal Security Service (FSB) head Igor Kochnev in order to suppress “possible terrorist acts,” the NAC said. It involved officers from the security forces, National Guard and police.

“The criminals were barricaded inside a private residence. In response to the security forces’ offer to surrender, they opened fire with automatic weapons,” the NAC statement said. 

Three law enforcement officers were killed in the shootout in addition to the four suspected terrorists. 

Security forces have seized weapons, ammunition and communication equipment from the residence. 

The suspected militants had arrived in Chechnya from abroad, Chechen leader Ramzan Kadyrov wrote on his official Telegram channel.

“Security forces knew in advance that members of illegal armed groups had arrived in the region from abroad. … Local residents also helped in uncovering the cell, informing [security forces] of suspicious individuals in one of the residences,” said Kadyrov. 

Kadyrov later added that the four suspects were originally from Grozny and had been “on the run” in Syria and other countries before returning to Chechnya to “plot terrorist attacks on orders from the West.” 

The Islamic State terror group has claimed responsibility for a series of attacks in recent years in Chechnya, a predominately Muslim republic in Russia’s North Caucasus region. An estimated 3,400 Russians fought in Syria and Iraq on the side of Islamic State and around 400 have returned home.

Islamic State is a terrorist organization banned in Russia.