KABUL, Afghanistan -- Defense Secretary Leon Panetta on Thursday pressured Pakistan to do more to root out the al-Qaida-linked Haqqani terrorist network from its territory, saying that U.S. officials are "reaching the limits of our patience."
The Haqqani group has been blamed for several attacks on Americans in Afghanistan, including last year's attack against the U.S. Embassy and NATO headquarters in Kabul. It also has ties to the Taliban and has emerged as perhaps the biggest threat to stability in Afghanistan.
Lawmakers from both parties have been urging the State Department to designate the Haqqani network a foreign terrorist organization.
The U.S. has given Pakistan billions of dollars in aid for its support in fighting Islamist militants.
Panetta made his comments at a news conference with Afghan Defense Minister Abdul Rahim Wardak, capping two days of blunt commentary on Pakistan.
"It is an increasing concern that the safe haven exists and that there are those – likely Haqqanis – who are making use of that to attack our forces," Panetta said.
"We are reaching the limits of our patience here, and for that reason it is extremely important that Pakistan take action to prevent this kind of safe haven from taking place and allowing terrorists to use their country as a safety net in order to conduct their attacks on our forces."
Panetta then underscored his point.
"We have made that very clear time and time again and we will continue to do that, but as I said, we are reaching the limits of our patience."
Wardak also said he thought Pakistan could do more to eliminate the sanctuaries that militants are using in Pakistan, saying the Pakistanis are in a better position to provide intelligence or take law enforcement or military actions.
"I do hope that gradually they will come to the conclusion to cooperate with us," Wardak said.
"If that cooperation starts, we will be able to disrupt their command and control, disrupt their training, disrupt their weapon recruitment and also will be able to eliminate or capture their leadership."
"Without doing that, I think our endeavor to achieve victory will become much more difficult."
Panetta arrived in Afghanistan on Thursday to take stock of progress in the war and discuss plans for the troop drawdown, even as violence spiked in the south.
Making his fourth trip to the war zone, Panetta acknowledged the increase in attacks and that the insurgents appear to be much more organized. But he insisted that the overall level of violence was down, and that commanders had expected the uptick.
Panetta said he wants to get an assessment of the situation from the top U.S. commander, Marine Gen. John Allen, and see how confident he is about NATO's ability to confront the threats both from the Taliban and the Haqqani network.
"I think it's important to make sure we are aware of the kind of attacks they're going to engage in ... as we go through the rest of the summer," Panetta told reporters traveling with him during a stop in New Delhi, India, on Wednesday.
Speaking to troops gathered at the airport in Kabul, Panetta kept up the drumbeat on Pakistan that began two days earlier during his visit to India. Panetta told the troops that "we have every responsibility to defend ourselves and we are going to make very clear that we are prepared to take them on and we've got to put pressure on Pakistan to take them on as well."
Panetta is arriving just a day after three suicide attackers blew themselves up in a marketplace in southern Afghanistan, killing 22 people and wounding at least 50 others. In the east, meanwhile, Afghan officials and residents said a predawn NATO airstrike targeting militants killed civilians celebrating a wedding, including women and children. A NATO forces spokesman said the coalition had no reports of civilians being killed in a raid.
Allen has to withdraw 23,000 American troops by the end of September, leaving about 68,000 U.S. military personnel in the country. Officials have said the bulk of the 23,000 probably will not come out until shortly before the deadline.
As those troops leave, Allen has said that Afghan forces will be used to fill in the gaps in the eastern and southwestern parts of the country. They will be buttressed by U.S. advisory teams that will work with the Afghan units.
Once the 23,000 U.S. troops depart, Allen is expected to review how the fighting season is going and then will begin to put together an analysis for President Barack Obama on how troop withdrawals will proceed next year.
Panetta also was scheduled to meet with U.S. Ambassador Ryan Crocker.
A senior U.S. official acknowledged Thursday that the recent increase in drone strikes on insurgents in Pakistan is due in part to frustration with Islamabad. Despite pressure from U.S. commanders, Pakistan remains reluctant to go after insurgents, particularly the Haqqani network, which was likely responsible for recent deadly attacks on U.S. forces.
Panetta's explicit description of frustration, while visiting neighboring India, appeared to signal a somewhat tougher stance and a suggestion that the U.S. is becoming even more willing and quick to strike terrorist targets inside Pakistan.
The defense secretary also joked with troops at the Kabul airport about the U.S. strike that killed an al-Qaida leader Monday, saying, "the worst job you can get these days is to be a deputy leader in al-Qaida, or for that matter a leader"
U.S. Defense Secretary Leon Panetta, center, arrives at Kabul International Airport in Kabul, Afghanistan Thursday, June 7, 2012. (AP Photo/Jim Watson, Pool)
U.S. Defense Secretary Leon Panetta walks off his plane as he arrives at Kabul International Airport in Kabul, Afghanistan Thursday, June 7, 2012. (AP Photo/Jim Watson, Pool)
U.S. Defense Secretary Leon Panetta, center right, speaks with U.S. Ambassador to Afghanistan Ryan Crocker, second right, and the head of NATO coalition forces in Afghanistan Gen. (AP Photo/Jim Watson, Pool)
U.S. Defense Secretary Leon Panetta, right, speaks with U.S. Ambassador to Afghanistan Ryan Crocker, center, and the head of NATO coalition forces in Afghanistan Gen. (AP Photo/Jim Watson, Pool)
U.S. Secretary of Defense Leon Panetta gestures while speaking during a press conference in New Delhi, India, on Wednesday, June 6, 2012. (AP Photo/Jim Watson, Pool)
U.S. Secretary of Defense Leon Panetta delivers a speech on Indo-U.S. Defense Relations at the Institute for Defense Studies and Analysis in New Delhi, India, Wednesday, June 6, 2012. (AP Photo/Jim Watson, Pool)
U.S. Defense Secretary Leon Panetta, second left, participates in a welcoming ceremony at the Ministry of Defense in New Delhi, India Wednesday, June 6, 2012. (AP Photo/Jim Watson, Pool)
U.S. Defense Secretary Leon Panetta pays tribute at the India Gate war memorial monument, in New Delhi, India, Wednesday, June 6, 2012. (AP Photo/Mustafa Quraishi)
U.S. Defense Secretary Leon Panetta, center, inspects Indian troops during a welcoming ceremony at the Ministry of Defense in New Delhi, India Wednesday, June 6, 2012. (AP Photo/Jim Watson, Pool)
U.S. Secretary of Defense Leon Panetta walks off his plane upon his arrival in New Delhi, India, Tuesday, June 5, 2012. (AP Photo/Jim Watson, Pool)