WASHINGTON — The United States Thursday admitted the situation in Pakistani tribal areas was "difficult and complex" as tensions with Islamabad escalated over US drone attacks on extremists and a border row.
Earlier, Pakistan's foreign ministry said there was "no justification" for escalated US drone strikes on its soil believed to be targeting militants blamed for plotting mass casualty attacks in Europe.
"We believe that (the attacks) are counter-productive and also a violation of our sovereignty," Pakistani foreign ministry spokesman Abdul Basit told reporters, calling on the United States to "revisit its policy."
White House spokesman Robert Gibbs habitually declines to comment on the strikes by unmanned drone aircraft armed with missiles, believed to be carried out by the CIA, and did not immediately respond directly to Basit's remarks.
But despite current elevated tensions, as the Afghan war moves into its 10th year, he praised Pakistan's role in the US anti-terror campaign.
"We understand the situation is difficult and complex. We are heartened by the activities that the government of Pakistan has undertaken to put Al-Qaeda under the type of pressure in the tribal areas that it has never faced before."
However, in a leaked report to Congress this week, the administration warned that Pakistani forces were avoiding "direct conflict" with the Afghan Taliban and Al-Qaeda in the lawless northwest tribal zone.
And it said the Pakistani military had continued operations against insurgents in South Waziristan, but added that soldiers stayed close to roads and that operations were progressing "slowly."
The United States has launched 27 drone attacks in a new wave since September 3, while more than 1,100 people have died in 143 strikes since the campaign began in August 2008.
Washington and Islamabad are also at odds over the killing of two Pakistani soldiers on Pakistani soil after they were mistaken for militants by a US helicopter crew.
The incident prompted Pakistan to close the main NATO supply route into Afghanistan. The crossing remains shut, despite apologies from US ambassador to Islamabad Anne Patterson and Admiral Michael Mullen, the chairman of the Joint Chiefs of Staff.
About 6,500 oil tankers and supply vehicles have been stranded in Pakistan for more than a week, waiting for the route to reopen to supplies heading for the 152,000 US-led troops in Afghanistan.
As the tankers have backed up, they have become vulnerable: about 120 NATO vehicles have been destroyed in gun and arson attacks over the past week as the Taliban militants step up efforts to disrupt the supply route.