Story highlights Rustam Magomedovich Aselderov pledged allegiance to ISIS in 2014, Russia says

He was wanted in connection with the 2013 terrorist attacks in Volgograd

(CNN) The leader of a North Caucasus ISIS branch was killed in a special operation conducted by Russian Federal Security Service forces in collaboration with the Ministry of Interior, the security service said in a statement Sunday.

Rustam Magomedovich Aselderov, known as Abu Muhammad, and four militants close to him were killed in an exchange of fire with government forces Saturday near Makhachkala, the capital of Dagestan, the statement from the FSB said.

Security forces surrounded a residence where the militants were hiding. During negotiations to surrender, the militants fired automatic weapons and government forces fired back.

Officials seized automatic weapons, large quantities of ammunition and explosives from the site, the FSB said.

Aselderov pledged allegiance to ISIS in 2014 before becoming the leader of the so-called "Vilayat Caucasus" in 2015, according to the FSB.

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