Police in Tajikistan say security forces have closed in on a former defense official who is believed to be hiding in a mountainous area following deadly attacks in and around the capital, Dushanbe.

The Interior Ministry said on September 5 that an "operation to apprehend and neutralize" Abduhalim Nazarzoda and his supporters was under way in the Romit Gorge, some 150 kilometers east of Dushanbe.

Authorities accuse Nazarzoda of leading the September 4 gun attacks and clashes that killed nine police officers and wounded six others in Dushanbe and the Vahdat district.

Police say security forces have killed 13 members of the "terrorist group" and arrested 32 others.

More than 500 weapons as well as ammunition and several vehicles were seized from the group during the operation, a police statement said.

Nazarzoda's 43-year-old brother, Mirzohayot Nazarov, allegedly also a member of the group, had voluntarily surrendered himself to government forces in Romit, police said.

Police said they had given Nazarzoda and his remaining seven or eight supporters an ultimatum to surrender.

Earlier on September 5, police officials said 150 additional troops had been deployed to Romit.

RFE/RL correspondents at the scene said at least three military helicopters were flying over the area.

Hours after the September 4 attacks, President Emomali Rahmon dismissed Nazarzoda as deputy defense minister "for committing a crime."

Nazarzoda, 51, had served as deputy defense minister since January 2014.

He had joined the security forces in June 1997 when the government and the opposition signed a peace accord to end the five-year civil war.

Meanwhile, the recently banned Islamic Renaissance Party of Tajikistan rejected claims that Nazarzoda was a member of the Islamic party.

The party said on September 5 that according to Tajik law, employees of law enforcement agencies and members of the armed forces are not allowed to join political parties.

The party expressed concern over the attacks and described them as "internal problems of the law enforcement agencies."

The Interior Ministry has also said the attack in Vahdat was not connected to the beating of Umar Bobojonov, the 23-year-old victim of an alleged police beating who died from his injuries in the Vahdat hospital late on September 4.

Relatives and friends of Bobojonov, a Vahdat native, say he was targeted by police on August 28 because of his beard.

Bobojonov's case sparked outrage in Vahdat, where dozens of people gathered outside the hospital on August 31 to demand the authorities arrest the culprits.