ISLAMABAD - Pakistans anti-terrorism efforts are seriously hampered by lack of assault helicopters such as Cobra and Apache and the United States inability to ensure adequate supply of spare parts to Islamabads existing choppers fleet. The US has provided some Cobra helicopters to Pakistan which it has used effectively in the tribal areas and Malakand division in fight against the Taliban militants but Islamabad has asked for more choppers from Washington as the existing ones are insufficient to carry on the war on terror successfully, said an official desiring not to be named. However, the US authorities had not been receptive to Pakistans demand for more assault choppers and their supply had been awaited in Islamabad for months now, he said. He said that not only the choppers non-provision was a major problem for Pakistani security forces but Washingtons inability to ensure smooth and timely supply of the spare parts to Islamabad for the existing fleet of its helicopters was also hampering the anti-terror endeavours. According to the official, the US authorities are now urging Pakistan to go for another major offensive in South Waziristan but they must know that the assault helicopters are the major pre-requisite for the success of any military operation in the tough mountainous terrain of Waziristan. He said that the United States should help Pakistan meet its defence related needs and requirements if it wanted the terrorists to be eliminated for once and all from the tribal areas. When asked about the possibility of military offensive in South Waziristan in near future against the Taliban in the wake of killing of their leader, Baitullah Mehsud, the official said that the security forces would do it and thats for sure but at the time when they deemed fit. The past difficult operations in Waziristan have made it all the more necessary to go into that area again after the terrorists after making all necessary arrangements, he said.