ISLAMABAD, Pakistan - Pakistani troops and tribesmen opened fire when two U.S. helicopters crossed into the country from neighboring Afghanistan, intelligence officials said Monday.
The alleged incident late Sunday in North Waziristan came as the Muslim country struggled to respond to a suicide bombing at a luxury hotel in the capital that killed at least 53.
Pakistan's army and the U.S. military in Afghanistan said they had no information on the reported incursion, which will likely add to tensions between Islamabad and Washington.
A spate of suspected U.S. missile strikes in Pakistan's border region and a raid by U.S. commandos that killed about 15 people have angered and embarrassed Pakistani leaders.
President Asif Ali Zardari is headed to New York to attend the United Nations General Assembly. The newly elected leader is also expected to meet President Bush.
The two intelligence officials spoke on condition of anonymity because they were not authorized to speak to the media. They said informants in the field told them of the incursion about one mile inside the disputed and poorly demarcated border in the Alwara Mandi area.
The helicopters did not return fire and re-entered Afghan airspace without landing, the officials said.
A week ago, U.S. helicopters reportedly landed near Angoor Ada, a border village in South Waziristan, but returned toward Afghanistan after troops fired warning shots.
A military spokesman said last week that Pakistani soldiers had orders to open fire in case of another cross-border raid by U.S. troops.
Meanwhile, suspicion hardened that al Qaeda or the Taliban were behind Saturday's blast at the Marriott hotel in Islamabad. Some 270 people were wounded, while the dead included the Czech ambassador and two U.S. Department of Defense employees.
Although no group claimed responsibility, officials and experts said the scale of the blast and its high-profile target were the hallmarks of media-savvy al Qaeda.
Senior al Qaeda leader Mustafa Abu al-Yazid threatened attacks against Western interests in Pakistan in a video timed with the recent anniversary of the Sept. 11, 2001, attacks in the United States.
Mahmood Shah, a former government security chief for Pakistan's tribal areas, said while the attack had "all the signatures" of an al Qaeda strike, homegrown Taliban militants probably had learned how to carry out an attack of this magnitude.
Al Qaeda was providing "money, motivation, direction and all sort of leadership and using the Taliban as gun fodder," he suggested.
The blast prompted foreign diplomatic and aid missions in Pakistan, as well as other expatriates, to review their security status.
British Airways said Monday it was temporarily suspending its flights to and from the country as a precautionary measure.
The airline, which offers six flights to Pakistan each week, did not face a direct security threat, company spokesman Suhail Rehman said.
Khalid Hussain Abbasi, a rescue official, said search teams finished a second round of checks at the gutted hotel and had not found more bodies Monday.
Dramatic surveillance footage released Sunday showed how the explosive-laden truck sat burning and disabled at the hotel gate for at least 3 1/2 minutes as nervous guards tried to douse the flames before they, the truck and much of the hotel forecourt vanished in a fearsome fireball.
