Police in Papua New Guinea fought off an attack by armed pirates who tried to hijack a Shell oil tanker as it was berthing at an island off the mainland. Shell Papua New Guinea operational manager George Talbot said the attack on the Petro Navigator charter vessel carrying 2,600 tons of fuel was of great concern. "Potentially it was a very dangerous situation -- firearms and oil tankers don't go well together," Talbot said. The company has suspended local fuel shipments until the attackers are caught. Talbot said four armed men boarded the vessel on Monday night as it was berthing on the island of Manus, 800 km (500 miles) north of Port Moresby. Police called to the ship struggled with the men and fired warning shots.