Pirates armed with AK-47 assault rifles attacked the crew of a supertanker waiting to load crude at Iraq's Basra oil terminal before making off with cash, an ocean crime watchdog says. The raid happened at night on 31 May about 10 nautical miles from Iraq's deep-water oil terminal where most of its crude oil is exported. "They tried to enter the bridge claiming to be policemen. The master denied them entry and the pirates became violent ... they assaulted the master causing him injuries and demanded money," the International Maritime Bureau (IMB) said in a report on Wednesday. The Nord Millennium was capable of carrying 300,000 tonnes of crude when fully loaded. A warship belonging to the US-led forces arrived to assist following a mayday signal. Jayant Abhyankar, deputy director of the IMB, told reporters the incident raised questions about security at the oil terminal, Iraq's main outlet for oil exports that provide nearly all of its income.