BOSASSO, Somalia, Oct 4 (Reuters) - Gunmen in Somalia's northeastern Puntland province hijacked a cargo plane carrying khat, a narcotic leaf, on Thursday after a business deal turned sour, a local official said. The attackers seized the plane, which had come from Ethiopia, in Puntland's port of Bosasso. They then flew 150 km (90 miles) west to another coastal town, Las Qorey, the chairman of the area, Muse Gelle Farole, told Reuters. "There was a conflict between the businesspeople that brought the khat to Bosasso, so one group of them hijacked the plane and made it land at Las Qorey," he said. Commonly chewed across the Horn of Africa region, khat is especially popular in Somalia where planes arrive daily from neighbouring countries with the lucrative commodity. Known for its relative stability in a country mired in chaos since the 1991 ousting of a dictator, semi-autonomous Puntland has nevertheless suffered a spate of pirate attacks off its coast in recent months. It was not known how many people were on board the plane.