WASHINGTON - While defending the airstrike inside Pakistan's territory,  the United States Wednesday regretted the loss of Pakistani troops at an army post along the Pak-Afghan border that came under U.S. attack. "This is a regrettable incident. We are sad to see the loss of life among the Pakistani military who are partners in fighting terror," spokesman Gonzalo Gallegoz said. But Defence Department press secretary Geoff Morrell defended the bombing. "Every indication we have is that this was a legitimate strike against forces that had attacked members of the coalition," he told a Pentagon press conference. "The bombs --mostly 500 pounds lazer-guided ones -- hit the target they were aimed at," said one unnamed official. Pakistan Wednesday strongly condemned the air strike in its Mohmand tribal area bordering Afghanistan and termed the it as "unprovoked and cowardly." The State Department spokesman said, "We are sure that military on both sides will look into the matter and review how to prevent recurrence and how to prevent the Taliban from using the area." The spokesman also said U.S Ambassador in Islamabad Anne Patterson has met with Pakistan's Foreign Secretary Salman Bashir to "discuss this incident". He referred to Pentagon for further details where the spokesman said the U.S. military will work with Pakistani military to get to the bottom of what actually happened. Quoting the air force officials in Afghanistan, he claimed early indications say they acted in self-defence. Spokesman Morrell described the relationship between the two countries as vital.         Rick Barton, a Pakistan expert at the Center for Strategic and International Studies, said the incident comes at a bad time, when the new Pakistani government is already overwhelmed trying to find its way. "The bad news with this kind of an incident is that it really distracts from the more important transition that's going on in Pakistan and it could really be exploited as an organizing tool to get people back to thinking the United States is the root cause" of problems in their country, Barton said. "It could easily be used as a provocation for some of the groups that are most anti-American and are outside the government as well," he said. The incident has inflamed anti-U.S. sentiment in Pakistan, where a new government is trying to reach out to tribal leaders in the border region to negotiate a peace deal. U.S. officials have expressed skepticism about the plan, and there have been repeated questions about Pakistan's commitment and ability to battle terrorists known to be hiding in the mountainous terrain. As recently as Monday, Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, repeated U.S. fears that if left unchecked, the ungoverned border region will likely spawn the next attack on U.S. soil. That area is also where some believe Osama bin Laden is hiding. Mullen, who has visited Pakistan three times since February, has talked at length with Gen. Ashfaq Kayani, the Pakistan Army chief.