US Defence Secretary Robert Gates has said that a victory over terrorism in Afghanistan was impossible as long as Taliban and Al-Qaeda guerrillas were hiding at their bases in Pakistan, report private TV channels. The US Defence chief claimed that the greatest threat of terrorism against the United States came from the remote tribal region of Pakistan. "If you asked me today, after the success we've had against Al-Qaeda in Iraq, where the greatest threat to the homeland lies, I would tell you it's in western Pakistan," Gates told Senate Armed Services Committee, adding, "Until the insurgency is deprived of safe havens, insecurity and violence will persist." The official urged the US administration to push the governments of Afghanistan and Pakistan towards cooperation to strengthen the control on the borders of the two states and make them less passable for terrorists. The head of the Pentagon hoped that the relations between Washington and Islamabad in the field of defence cooperation would improve. According to CNN, Gates said that he could see "no downside" to efforts to create an Afghan-Pakistani-US patrol on the troubled Afghanistan-Pakistan border. On Monday, Afghan Defence Minister Abdul Rahim Wardak told reporters at the Pentagon that the three countries had been discussing such as patrol. Asked about the discussions at Tuesday's hearing, Gates said that the idea had not come up when he was in Afghanistan last week. Despite tension over US incursions into Pakistan, Gates said that Pakistan had increased efforts on its side of the border to go after extremists, insisting that Pakistan and the United States needed to work together on the problem. "Regardless of effectiveness, the mere presence and willingness to fight has reduced pressure on the Afghan side," Gates told the Committee. "Pakistan has to be part of the strategy." Gen James Cartwright, Vice-Chairman of the Joint Chiefs of Staff, who also appeared at the Senate hearing, said, "We are starting to see cooperation between the militaries we've never had." AFP adds: Gates cautioned against a rapid US military expansion in Afghanistan, stressing instead the need to build up the Afghan army. Cartwright also told lawmakers that there were practical obstacles to a rapid shift of forces from Iraq to Afghanistan which could not be fully overcome even if a US drawdown in Iraq were accelerated. He said those obstacles included a lack of the support forces and equipment, such as helicopters and vehicles. Gates, meanwhile, suggested that a rapid US military expansion could be counter-productive in a country with a history of resistance to outsiders. He said US forces might simply be too thinly stretched to handle the redeployment. Gates, who testified alongside Cartwright, said he learned about senior US commander in Afghanistan, General David McKiernan's new requirement only after a visit to Kabul last week. He said he believed it could be met by the spring or summer of next year. Asked whether the commander's request could be met more quickly if US forces were withdrawn at a faster pace from Iraq, Cartwright said, "We would not be able to meet the entirety of that request." "We could meet part of it. The challenge is the infrastructure and the (equipment and personnel) and moving them," he said.