The meeting Tuesday came after several weeks of Pakistani offensives against militants in the country's volatile northwest - an effort American officials welcomed but said Thursday has come nowhere near to stemming growing problems near the Afghan border.
The meeting aboard the USS Abraham Lincoln was the latest of several between Adm. Mike Mullen, chairman of the Joint Chiefs of Staff and General Ashfaq Kayani, chief of staff of the Pakistani army.
U.S. defense officials said that this time Mullen also brought Gen. David Petraeus, the top American commander in Iraq, who will soon leave to become the senior commander in the Middle East; Adm. Eric T. Olson, head of the Special Operations Command; Gen. David McKiernan, NATO's commander in Afghanistan; Lt. Gen. Martin E. Dempsey, acting commander of American forces in the Middle East; and Rear Adm. Michael LeFever, American military liaison in Pakistan.
A U.S. official familiar with the discussion said Tuesday's meeting was "more collaborative," compared to a similar meeting a month ago when Mullen took a "more firm tone" in warning Kayani that Islamabad was not doing enough to counter militants waging cross-border attacks in Afghanistan.
Pakistan's military said in a statement that it was a "prescheduled meeting aimed at discussing security matters at strategic level. The discussion was held in an open and cordial manner."
Pakistani army spokesman Maj. Gen. Athar Abbas said the commanders analyzed the security situation in the region and that no new agreements were struck.
U.S. officials declined to say what, if any, decisions had been made and only confirmed on condition of anonymity that the daylong meeting had taken place. One official said it was not prompted by any recent political or military events, but rather planning for it began during Mullen's previous meeting with Kayani - a month ago in Pakistan.
Political turmoil has worsened in Pakistan - and violence in both Pakistan and Afghanistan - have increased since the last meeting.
Suspected militants bombed a bus carrying prisoners in northwest Pakistan on Thursday, killing eight people, as fighting between security forces and extremists flared across the country's tribal belt.
The fresh violence comes days after ex-president Pervez Musharraf, a longtime U.S. ally, resigned as president, triggering a scramble for power that caused the country's ruling coalition to collapse.
Pakistan's five-month-old government initially sought to calm militant violence by holding peace talks. But U.S. officials have been pressing for tougher action against insurgents. Pakistan's army is now fighting insurgents in at least three areas of the northwest and claims to have killed several hundred militants in the recent offensives.
"They are doing more and becoming more effective," one U.S. defense official said of the effort. "But there is still a long way to go" in the tribal areas.
He added that Mullen is concerned about the worrisome trend of a growing and more diverse group of foreign fighters who are carrying out more complex attacks against allied forces in Afghanistan - what Mullen has called "a syndicate" of extremists.
The second U.S. official said Pakistanis need to launch a "more concentrated effort."
Meanwhile, a four-day rolling battle in southern Afghanistan involving U.S. coalition and Afghan forces killed more than 100 militants, the coalition said Thursday.
Militants wielding rocket propelled grenades, guns and mortars attacked the joint patrol in the southern province of Helmand multiple times starting Monday and continuing through Thursday, the coalition said. The combined force called in fighter aircraft for support.
The coalition statement said no Afghan, coalition or civilian casualties had been reported.
Also, the Pakistani military said it killed more than 20 militants in a restive northwestern valley. Army spokesman Maj. Murad Khan said the insurgents died in three separate clashes on Thursday in the Swat valley, where troops have been battling Islamic extremists for months.
Khan said helicopter gunships fired on militants riding in two vehicles and in a suspected hideout. He said no security forces have been killed.