US Defence Secretary Robert Gates warned Wednesday that South Asian militant groups were seeking to destabilise the entire region and could trigger a war between nuclear-armed Pakistan and India. Reflecting anxiety in the region about New Delhi's reaction if it were attacked by a militant group with roots in Pakistan, Gates said restraint by India could not be counted on. Gates said militants under Al-Qaeda's "syndicate" -- which includes the Taliban in Pakistan and Afghanistan, as well as Pakistan-based Islamist group Lashkar-e-Taiba -- posed a danger to the region as a whole. They are trying "to destabilise not just Afghanistan, not just Pakistan, but potentially the whole region by provoking a conflict perhaps between India and Pakistan through some provocative act," Gates said during a visit to New Delhi. "It's important to recognise the magnitude of the threat that the entire region faces," he said following talks with his Indian counterpart, A.K. Antony. India and Pakistan have fought three wars since their independence in 1947 and tension spiked again in 2008 when militants -- that New Delhi identified as belonging to Lashkar-e-Taiba -- attacked the city of Mumbai, killing 166 people. India did not mobilise forces, unlike in 2001 when it massed troops on the border with Pakistan after an attack on its parliament. This drew praise from Gates, but he said such restraint might not be repeated next time. "I think it's not unreasonable to assume India's patience would be limited were there to be further attacks," Gates warned. New Delhi suspects the Pakistani intelligence service of supporting terror groups that target India and has consistently called on Islamabad to crack down on militants operating on its soil. Gates described India as a vital partner in the struggle against extremist threats, expressed appreciation for its economic aid to Afghanistan and said that he had discussed how to bolster US-India military cooperation. During his two-day trip to India, Gates has also reassured leaders in New Delhi that Washington will not abandon Afghanistan despite a timeline for the withdrawal of US troops. In separate meetings with Prime Minister Manmohan Singh and Foreign Minister S.M. Krishna on Tuesday, Gates discussed "regional security" and offered reassurances over the target date of July 2011 for starting a drawdown of American forces, a US defence official said. Gates, mindful of India's concerns about an early US exit, pledged the United States would remain committed to Kabul with major economic and diplomatic support even as its military presence is gradually scaled back, the official told reporters. He told Singh and Krishna that "we intend to be involved in the region for a very long time," said the official, who spoke on condition of anonymity. The United States, which armed Afghan Islamic fighters against Soviet forces in the 1980s, had made the mistake of turning away from Afghanistan after the Soviets were driven out but would not repeat that mistake, Gates said, according to the official, who attended the meetings. The prime minister and foreign minister for their part offered to keep up India's major reconstruction aid for Afghanistan, the official said. US officials said the visit reflected a blossoming relationship between the two countries that has dramatically transformed since the mutual unease of the Cold War. Defence ties have expanded following the attacks of September 11, 2001, and a deal in July between the two countries helped clear the way for the sale of hi-tech US weaponry to India. Gates told the prime minister and foreign minister that there were more opportunities for defence trade and promised to help remove US legal barriers blocking India's access to some military technology, defence officials said. A number of cooperation agreements were under discussion that would permit India to purchase a wider array of weaponry with sophisticated technology, the officials said.