A devastating earthquake triggered landslides, toppled an apartment building and flattened villages of mud-brick homes Saturday, killing more than 18,000 people across a mountainous swath touching Pakistan, India and Afghanistan.

The casualty toll from the 7.6-magnitude tremor rose sharply Sunday as rescuers struggled to dig people from the wreckage, their work made more difficult as rain and hail turned dirt and debris into sticky muck. Maj. Gen. Shaukat Sultan, Pakistan's chief army spokesman, told Pakistan's Geo TV network early Sunday that more than 18,000 had been killed _ 17,000 of them in Pakistani Kashmir, where the quake was centered. Some 41,000 people were injured, he said.

For hours, aftershocks rattled an area stretching from Afghanistan across northern Pakistan into India's portion of the disputed Himalayan region of Kashmir. Hospitals moved quake victims onto lawns, fearing tremors could cause more damage.

The earthquake, which struck just before 9 a.m. Saturday, caused buildings to sway for about a minute in the capitals of Afghanistan, Pakistan and India, an area some 625 miles across. Panicked people ran from homes and offices, and communications were cut to many areas.

Most of the devastation occurred in the mountains of northern Pakistan. The U.S. Geological Survey said the quake was centered about 60 miles northeast of the capital, Islamabad, in the forested mountains of Pakistani Kashmir.

"It is a national tragedy," Sultan said earlier. "This is the worst earthquake in recent times."