KABUL, Afghanistan (AP) — An Afghan official says that Pir Sayed Ahmed Gailani, chief of Afghanistan’s High Peace Council, tasked with negotiating an end to the country’s protracted conflict, has died at age 84.

Mohammed Karim Khalili, deputy head of the council, told The Associated Press that Gailani died in Kabul earlier Friday. The exact cause of death was not immediately reported but he had been ill.

Gailani rose to prominence during the 1980s Soviet invasion of Afghanistan as a resistance leader and the founder of the National Islamic Front of Afghanistan, one of seven U.S.-backed groups fighting Russian invaders. The war ended with the Soviet withdrawal in 1989. Three years later Afghanistan’s pro-Moscow government collapsed and the resistance leaders took power.

Gailani had been a strong proponent of peace talks with the Taliban.