Cross-border firing from Afghanistan hit the tent of a nomad family on the Pakistan side of the frontier, killing two women and injuring at least four children, two Pakistani officials said Sunday.

The Pakistani officials said four rockets or shells were apparently fired by the U.S. military in fighting with suspected militants in Afghanistan's eastern Khost province late Saturday, and one hit the nomads' tent at Bangi Dar, in Pakistan's North Waziristan tribal area.

The officials — one an intelligence official, the other a local government administrator — spoke on condition of anonymity as they weren't authorized to speak to media. There was no immediate confirmation from the Pakistan government or military.

In Kabul, Lt. Mike Cody, a spokesman for the U.S. military in Afghanistan, said that a security post along the border in Khost was attacked from the Pakistani side at 4 p.m. on Saturday, and the U.S. military, coordinating with the Pakistani military, used artillery to return fire at the point of attack.

Cody said there were no reports of casualties on either side.

Pakistan is a key ally in the U.S.-led war on terrorism but does not allow U.S. troops to operate on its side of the rugged and ill-defined border where foreign militants are believed to be hiding.

About 20,000 U.S. troops are in Afghanistan hunting for remnants of the ousted Taliban militia and Al Qaeda fugitives.

Fire from coalition forces hunting the rebels has sometimes landed in Pakistani territory.

Last month, Pakistan protested to the U.S. military in Afghanistan over two air strikes — one on a village in North Waziristan that killed eight people, and the second, a missile strike that hit a village in Bajur tribal region where top Al Qaeda figures were suspected to be meeting. Thirteen civilians died, and according to Pakistan, five foreign militants, including one Al Qaeda operative on the U.S. most-wanted list.

The intelligence official said that in Saturday's incident, four U.S. rockets landed in Bangi Dar, north of Miran Shah, the main town in North Waziristan, and one hit the tent. He confirmed Cody's report that there a coalition post in Afghanistan had been fired at, but did not say whether the fire came from within Pakistan.

He said two women died and the four injured children were being treated at a hospital in Mir Ali, a town in North Waziristan. He had no details about their conditions.

The government administrator gave the same information, but said four artillery shells had landed in the area, and five people — not four — were injured, the other being a 26-year-old woman.

Top Pakistan army spokesman Maj. Gen. Shaukat Sultan had no information about the report and said he was trying to find out details.