US and Pakistani armed forces have agreed to conduct a joint investigation into a US airstrike that killed 11 Pakistani soldiers this week, US Assistant Secretary of State Richard Boucher said on Friday. “There is an understanding between the militaries that they will conduct a joint investigation and the foreign ministers agreed that that was the right way to go,” he told reporters after a meeting between US Secretary of State Condoleezza Rice and her Pakistani counterpart Shah Mehmood Qureshi in Paris. Pakistan, a US ally, has denounced Tuesday's attack on a border post in the Mohmand tribal region as “unprovoked and cowardly” and said it could undermine their cooperation in the battle against Al-Qaeda and the Taleban. US officials have expressed regret for the deaths but have said that the strike was a legitimate action carried out in self-defence after US troops on the Afghan side of the border came under attack. Qureshi, who like Rice was in Paris to attend an Afghan donors conference on Thursday, said a US drone had instead shot at Pakistan soldiers and that such “tragic incidents” only helped the extremist cause. “The people who have died have been identified and there is no confusion about their identity. How can you deny facts? Those facts will be put forward when the joint investigation takes place and hopefully we will get to the bottom of the story,” he said before his talks with Rice. While saying that he thought a joint investigation would be useful, Qureshi also called on the US to cooperate much more with the Pakistani military. Washington has invited Pakistani and Afghan officials to help look into the attack, which occurred in a region where Al-Qaeda and Taleban militants are believed to have taken refuge. Qureshi said the killings would not help relations with Washington and risked undermining Pakistan's efforts to bring peace to the semi-autonomous tribal areas bordering Afghanistan. “These incidents do not help (relations). We want to get the support of the local population. Such incidents damage this environment and do not help,” he said. Some US officials have questioned whether the Pakistan government is going too far in its efforts to improve ties with leaders in the tribal regions and is effectively enabling the militants to regroup. The new Pakistani government has been negotiating with ethnic Pashtun tribes to get them to press the militants to give up a campaign of violence in Pakistan in which hundreds of people have been killed over the past year.