The attack on Islamabad's Marriott Hotel used over 500 kilogrammes (1200 pounds) of high intensity explosives and was likely carried out by Al-Qaeda, investigators said Sunday. Nobody has claimed Saturday's suicide truck bombing of the five-star hotel in central Islamabad which left over 60 people dead, but investigators said it was typical of Osama bin Laden's Al-Qaeda network. "It has the hallmarks of Al-Qaeda," a senior official involved in the investigation said. "It was an Al-Qaeda style bombing and was similar to the attack on the Federal Investigation Agency (FIA) office," he said, referring to a suicide attack in March in the eastern city of Lahore which left 20 people dead. The Lahore attack was blamed on Pakistani Al-Qaeda leader Qari Zafar, who was also believed to be responsible for the March 2006 bombing of the US consulate in Karachi. Zafar has a five million US dollar bounty on his head. Investigators said between 500 and 600 kilogrammes of explosives were used in Saturday's attack which left a crater measuring 20 metres (70 feet) wide by eight metres deep in front of the hotel.