All tension with Pakistan aside, the US shows no sign of stopping its use of unmanned drones to kill al-Qaeda members in Pakistan’s tribal areas.

 Top national security officials fled the steamy debt debate in DC to take part in the Aspen Security Forum in cool Colorado last week, but they couldn’t escape the growing controversy.

Cradled amid Aspen’s pine-covered peaks and the Washington elite, with the soothing sounds of the Roaring Fork River as a backdrop, their talk was unusually frank.

Douglas Lute, President Barack Obama’s top advisoe on Pakistan, said his plan was to increase covert action in the tribal areas to take advantage of al-Qaeda’s disarray following the death of Osama Bin Laden.

 “We need to go for the knock-out punch in this window of opportunity,” said the deputy national security adviser, adding that the goal was to take out three to five al-Qaeda leaders in the next six months.

His comments were widely interpreted to refer to the use of drone strikes, which the Obama administration does not publically acknowledge.

 A day earlier, Dennis Blair, a former US director of National Intelligence, said the strikes are so unpopular with the Pakistani public that they are increasingly counterproductive.

He said they should only be carried out with the co-operation of the Pakistani government, which has publically opposed US unilateral action on its territory.

 According to the Long War Journal, which tracks air strikes in Pakistan, there have been 43 so far this year with more than 300 people killed, 30 of them civilians.

Former National Security Adviser Stephen Hadley, former Homeland Security Advisor Fran Townsend, and former Congresswoman Jane Harman all defended the use of drones as a necessary tool in the fight against al-Qaeda.

 Pakistan’s Ambassador to the US, Husain Haqqani, acknowledged the strikes had taken out key al-Qaeda members but said his government wanted fewer of them because they were hurting support for the war.

Speaking on a panel entitled “The View from Abroad”, Haqqani complained about the US attitude towards his country, as displayed at the forum.

 “You have one hour for the “view from abroad”, whereas the rest of the time you sit and talk about what to do to us. That’s not how partnerships are formed.” he said, addressing what has become a common complaint in Washington: that Pakistan is not doing its share in the hunt for al-Qaeda members.

The American Civil Liberties Union is taking the issue of drones to the courts. The ACLU filed a lawsuit against the federal government on behalf of the father of Anwar al-Awlaki, an American-born Muslim religious leader reportedly the target of a drone strike in Yemen last May. Alwaki has a large global following and has called for attacks.

 “Drones are highly problematic,” Anthony Romero, the ACLU's executive director, told the forum. “When we think we can drop bombs on a sovereign place like Yemen - as I understand, there has not been a declaration of war on Yemen - hunting an American citizen to deprive him of life.”

Like the ACLU, the UN opposes these targeted assassinations because there is no judicial oversight to protect those who are targeted.

These and other critics are turning up the heat on the Obama administration as it increases its use of drones. You can feel the temperature rising - even in the cool mountains of Aspen.