WASHINGTON, June 12: The United States has regretted the loss of life in the latest air strike in Mohmand agency but senior US officials have also indicated that this was not a knee-jerk reaction but a planned operation, which may be repeated whenever militants try to enter Afghanistan.

The Pentagon has described the June 10 attack as “legitimate” and in “self-defence” while the State Department called the deaths “regrettable” and underscored the need for better communication between forces deployed on both sides of the Afghan border.

In a report posted on its website on Thursday, the Pentagon quoted a senior US military official in Afghanistan as saying that they were running company- and battalion-sized operations in the area where 11 Pakistani soldiers were killed on Tuesday.

“There’s a lot of infiltration that goes across the border either side,” the official said. “So we run operations on our side of the border in combination with the Pakistanis on the other side.”

On Tuesday, when US forces were targeting a Pakistani military post in Mohmand agency, America’s top military official, Admiral Michael Mullen, gave his take on the situation in Fata, which partially explains why the US military responded so strongly to prevent alleged militant incursions into Afghanistan.

Admiral Mullen, chairman of the US Joint Chiefs of Staff, claimed at a gathering of defence correspondents in Washington that Al Qaeda was using Pakistan’s tribal belt for planning attacks against the United States and that Islamabad was unable to take immediate action to prevent such an attack.

“I believe fundamentally if the United States is going to get hit, it’s going to come out of the planning that the leadership in Fata is generating, their planning and direction,” the admiral said. “I’m not saying it is guaranteed it’s going to happen … but clearly we know the planning is taking place.”

A transcript of the admiral’s briefing, made available on Thursday, also quoted him as saying that peace talks between Pakistan and the insurgents were allowing fighters to cross more freely into Afghanistan.

This is so far the starkest assessment of the situation in Fata and of its implications for the United States by any senior US official.

While reporting on the admiral’s comments, the US media noted on Thursday that recently US defence officials have acknowledged a growing tension in the Pentagon over conditions in Pakistan.

They noted that the US administration has been pushing Pakistan quietly for months to accept its assistance in developing a counter-insurgency plan.

Admiral Mullen said that, as one of the first steps in that effort, the Pentagon expected to send 20 to 30 US military trainers to Pakistan. But he conceded that such moves were unlikely to produce immediate results, particularly because the new Pakistani government was beset by so many problems that it could not focus on the situation in Fata.

The admiral did not say that the United States will compensate for Pakistan’s lack of focus by ordering its own military strikes whenever there was a major militant activity in Fata, but other US officials have.

Meanwhile, the Heritage Foundation, a Washington-based conservative think-tank, warned on Thursday that the US military action in Mohmand agency “may strain” US-Pakistan relations.

“Given the constant crossing back and forth by the terrorists between countries and the lack of government control of the tribal areas in Pakistan, this type of incident does not come wholly unexpected,” the report said.

“Instead of engaging in tactical negotiations with militants to buy time, Pakistan needs to develop a strategic approach to dealing with the tribal areas that is closely coordinated with and supported by the United States.”