WASHINGTON (AFP) - Any future terror attack against US interests would most likely be carried out by militants based in Pakistan's restive tribal belt bordering Afghanistan, the top US military official said Tuesday. Admiral Michael Mullen, Chairman of the Joint Chiefs of Staff, told a Press conference that tribal groups with ties to Al-Qaeda in Pakistan's Federally-Administered Tribal Areas represent the worst security threat to the United States. "I believe fundamentally if the United States is going to get hit, it is going to come out of the planning of the leadership in the FATA - Al-Qaeda specifically," he told reporters. "That is a threat to us that must be dealt with," Mullen said of the radical groups sheltering in the no-man's land between Pakistan and Afghanistan. But Mullen said he was not satisfied with progress in subduing militants there. Pakistan's government, under the leadership of new prime minister Yousuf Raza Gilani, launched peace talks with the militants after coming to power in March. The new government, Mullen said, "has significant challenges as it gets under way, and at the same time is looking to the best way to best deal with this challenge." Insurgents who find refuge in FATA regularly supply weapons and ammunition into Afghanistan, while a number of suicide bombers have come from Afghan refugee camps based in Pakistan. Mullen recognized that a solution to the problem is a long way off. "We're not going to solve it overnight," Mullen said. "There is no simple answer, no easy solution here," he warned, adding that at all cost, "it has got to be dealt with." Mullen held two days of counter-terrorism talks with Pakistani army top brass in Islamabad last week, on his third trip to the nuclear-armed nation since parliamentary polls in February. The United States and Western allies have warned the new government's efforts to strike peace deals with extremists will lead to an increase in cross-border attacks into Afghanistan.