ISLAMABAD >> U.S. drones fired 10 missiles at a house in a Pakistani tribal region near the Afghan border on Friday, killing at least 25 people, Pakistani intelligence officials said. The strike came a day after Pakistan’s army chief denounced such attacks, and could further sour already deteriorating relations between Washington and Islamabad.

Also Friday, hundreds of militants attacked a checkpoint in a northwest Pakistani district along the border overnight and into the morning hours, killing 14 security troops, officials said — a show of insurgents’ continued strength despite army offensives against them.

The latest U.S. missiles hit Spinwam village in North Waziristan, a tribal region home to Islamist militants that target American and NATO troops in Afghanistan. The three intelligence officials said civilians were believed to be among the dead, and that several people also were wounded. The reported death toll was relatively high for an American missile strike.

The U.S. rarely acknowledges the CIA-run missile program, meaning the usual sources for the confirmation of strikes are Pakistani intelligence officials, who speak on condition of anonymity because they do not have permission to speak to the media. That information from the region is nearly impossible to verify independently. The area is remote, rugged and dangerous, and access to it is legally restricted.

Although Pakistan has long denounced the drone-fired missile strikes as violations of its sovereignty, it is widely believed to secretly cooperate with at least some of the attacks.

But Pakistan-U.S. relations have sunk to new lows this year after an American CIA contractor in January shot and killed two Pakistanis he said were trying to rob him. A March missile strike that allegedly killed dozens of innocent tribesmen also angered Pakistani leaders.

The U.S. seems intent on using the drones, nonetheless. Last week, just two days after a visit to Washington by Pakistan’s spy chief, a U.S. missile strike killed several alleged militants in the northwest and drew condemnation from the Pakistani Foreign Ministry.

During a visit here Wednesday, Adm. Mike Mullen, the chairman of the U.S. joint chiefs of staff, accused Pakistan’s military-run spy service of maintaining links with the Haqqani network, a major Afghan Taliban faction.

Pakistan’s military-run Inter-Services Intelligence spy agency has had links to the network’s leaders that date back to the 1980s Soviet occupation of Afghanistan, when the group was also supported by Washington. But after the Sept. 11, 2001, attacks, Pakistan has insisted it has cut those ties.

Still, many analysts and U.S. officials suspect Islamabad may be trying to maintain its links to the Haqqanis so that it can use them as a means of retaining influence in Afghanistan — and keeping a bulwark against archrival India — after the Americans leave.

A Pakistani army statement later rejected what it called “negative propaganda” by the United States, while army chief Gen. Ashfaq Parvez Kayani said his troops’ multiple offensives against insurgent groups in the northwest are evidence of Pakistan’s “national resolve to defeat terrorism.”

Kayani also slammed the ongoing U.S. missile strikes. Those strikes nearly always hit North Waziristan, where the Haqqanis are based and the one tribal region along the Afghan border where the army has not staged an offensive despite U.S. pleas.

While officials from both nations have raised the level of rhetoric, they also say they want to keep the partnership intact. Washington needs Pakistani support to be able to begin withdrawing troops from Afghanistan this summer, while Islamabad relies heavily on U.S civilian and military aid.

The fighting in Lower Dir underscored the strength of Islamist militants in the border region, where al-Qaida and Taliban fighters have long proliferated. Pakistan’s army has staged operations in Lower Dir and the adjacent tribal belt, but it has struggled to keep the peace after initially clearing the insurgents.

Officials from the police, government and intelligence agencies said some fighting was still going on Friday morning. They did not know how many militants died in the clashes in Lower Dir’s Khankai area. State-run Pakistan TV said security forces had launched a search operation to track down the lead attackers.

The four officials spoke on condition of anonymity because they were not authorized to speak to media on the record. Army officials did not immediately respond to requests for comment Friday.