At least two Americans and two Pakistani soldiers and were wounded.
"There was a flag meeting in Kurram agency (on the Pakistani-Afghan border). After the meeting, everyone was returning back and they were fired upon by miscreants (militants or insurgents), Maj. Gen. Waheed Arshad, chief spokesman of the Pakistani armed forces, told CBS News. "One U.S. soldier and one Pakistani soldier were killed, and three Pakistani and three U.S. soldiers were injured."
Afghan military officials also attended the talks to discuss recent fighting between Afghan and Pakistani forces that the government in Kabul says has killed at least 13 people inside Afghanistan — inflaming already poor relations between Pakistan and Afghanistan.
NATO's International Security Assistance Force in Afghanistan said it could confirm ISAF casualties but not the exact number of injured or killed.
Maj. William Mitchell, a spokesman at the U.S. military base in Bagram, Afghanistan, said officials were trying to verify conflicting reports of violence.
Rahmatullah Rahmat, governor of the Afghan border province of Paktia, said that he, U.S. military advisors and Afghan army leaders traveled by helicopter to Pakistan for the meeting.
He said that after the meeting finished, gunmen opened fire on the group as they were heading toward their helicopters. Rahmat reported two American dead and two wounded.
He said that American soldiers returned fire.
Arshad said that Pakistan has ordered a high-level inquiry into the incident. He said initial reports from Afghanistan that a Pakistani soldier had opened fire on the American troops were "malicious."
He had no details on the conditions of the wounded soldiers or their identities. He said the Americans had been shifted to Afghanistan for treatment.
"The latest information that I have got is that one Pakistani soldier died of his wounds, and one American soldier died of his wounds," Arshad said.
"Efforts are being made to determine from where the firing came from and who carried it out. The area has been cordoned (off)," he said.
Islamic militants, including supporters of the Taliban and al Qaeda, are active in the lawless border region.
Meanwhile, a general strike paralyzed Karachi and closed businesses in other major Pakistani cities Monday as discontent grew over President Gen. Pervez Musharraf's ouster of the chief justice and a weekend of violence that left 41 people dead.
Shops were shut and traffic was thin on the roads in the southern port city, where security forces have authority to shoot rioters on sight, after the weekend witnessed the worst political violence in Pakistan in years.
Security forces on Saturday took no action as rival groups demonstrating over an abortive visit to Karachi by suspended Chief Justice Iftikhar Mohammed Chaudhry fought fierce clashes that also wounded more than 150 and caused widespread damage to property. Opposition parties blamed the government for the violence and called a nationwide protest strike Monday.
"There is a complete strike in Karachi," said Azhar Faruqi, the city police chief.
He reported that law and order was improving — after the unrest took an ominous ethnic turn on Sunday with clashes between Urdu-speaking Mohajirs linked to a pro-government party and Pashtuns, whose rivalry has caused bloodshed here in the past.
Officials said the strike was being observed in towns and cities across southern Sindh province, of which Karachi is the capital. It was also observed, in varying degrees, in Islamabad and the capitals of Pakistan's other three provinces, Lahore, Peshawar and Quetta.