A moderate earthquake Sunday shook Pakistan's capital and the country's northwestern region, still recovering from the devastating Oct. 8 temblor. There were no report of injuries or damage.

The quake registered magnitude 5.2, said the state-run Seismological Center in the northwestern city of Peshawar.

Buildings shook in Islamabad, where some residents ran out of their homes, local Geo television reported. The quake was centered 125 miles northeast of Peshawar, the seismological center said.

It was felt only slightly in Muzaffarabad, the capital of Pakistan-administered Kashmir, near the center of the 7.6-magnitude quake in October that killed an estimated 87,000 people and left more than 3.5 million homeless.

U.S. Ambassador Ryan Crocker was visiting the U.S. Mobile Army Surgical Hospital set up to help survivors of the October quake in Muzaffarabad, but apparently no one in the hospital felt Sunday's temblor.

Crocker praised Pakistan's cooperation with the U.S. in the war on terror and said the American humanitarian mission "is our turn to reciprocate the spirit, and we are happy to give whatever is needed for reconstruction and rehabilitation."

"I am pleased to have this opportunity to be with our men and women on this Christmas," he said. "They are working happily to help the people affected by the (October) earthquake."

In recent days, the Pakistani army, with the help of U.S. helicopters, NATO troops, U.N. and other aid groups, has stepped up delivery of winterized tents, warm clothes, food and medical items to survivors as temperatures dropped below freezing.

The U.N. estimates 2.5 million people are living in tents below elevations of 5,000 feet, while 350,000-400,000 others are still at risk in higher areas where snow has started falling.

Navy Rear Adm. Michael LeFever, the senior U.S. commander of the humanitarian mission, said 1,550 U.S. troops would remain in the quake zone "as long as the Pakistani government wants us to be here."

"Our relief work is planned until March, as the Pakistani government asked us to be here through the winter," he said.