Washington, Sept 30 : International laws through the UN Charter allow the US to launch unilateral actions inside Pakistan as Washington considered insurgency in Pakistan's tribal areas - FATA - as the greatest danger confronting the West, said US Defence Secretary Robert Gates.
According to him, the US was willing to send its troops to root out extremism if it felt the need to do so.
Gates said this at two separate statements and during a hearing at a Senate panel.
Laying emphasis on the importance of working with Pakistan, he said the US was cooperating with the new Pakistani government to defeat militancy and would continue to do so.
At the Senate panel hearing, Gates agreed with Democratic Senator Jim Webb who had told him that the UN Charter - under which the US operates in Afghanistan - gave the US the right of self-defence where a foreign government was either unable or unwilling to take care of international terrorist activity inside its borders.
Gates said: "The authorities we have been granted were carefully coordinated over a protracted period of time in the interagency."
Separately, he told the Senate Armed Services Committee: "I would simply assume that...........appropriate international law was consulted by the State Department."
In a written statement before the committee, Gates said that "insecurity and violence" in the Afghan-Pakistan region "will persist..........until the insurgency is deprived of safe-havens" in Pakistan's tribal areas.
And, the US defence chief told the National Defence University in Washington that the United States had to act against terrorists hiding in Afghanistan and Pakistan because it could not afford to fail. "To be blunt, to fail - or to be seen to fail - in either Iraq or Afghanistan would be a disastrous blow to our credibility, both among our friends and allies and among potential adversaries," he said.
Earlier, Gates explained that Pakistan could not defeat terrorism on its own. "Pakistani government doesn't have the capacity to launch unilateral operation against militants inside its borders," he said.
He noted that the US depended on Pakistani road links to send 80 per cent of its supplies and 40 per cent of fuel into Afghanistan. He said that while the US was looking for alternative channels, it could not afford to ignore Pakistan.