A massive earthquake rocked Afghanistan and northwestern Pakistan Monday night, killing about 1,800 people and injuring 2,000. Up to 2,000 others were reported missing.

Kabul television later reported 5,000 hurt. The death toll could reach 4,800, Geneva-based United Nations spokeswoman Elisabeth Byrs said, citing Afghan authorities.

Officials said the death toll was high because many people were at home when the quake struck at 7:26 p.m. Monday, and during the frequent strong aftershocks overnight.

"People were caught in their homes," Nigel Fisher, a senior U.N. official in Afghanistan, said.

The Afghan Defense Ministry said 600 bodies were recovered from villages still shaking from aftershocks.

There were no reports that any Americans or members of the international peacekeeping force had been killed or injured, but the U.S. Army at Bagram air base sent a small assessment team to the affected area to decide if American troops could help rescue and recovery efforts, spokesman Maj. Bryan Hilgerty said. The U.S. administration also has pledged assistance to the interim government and local people dealing with the tragedy, U.S. special envoy Zalmay Khalilzad said.

An estimated 10,000 people are now homeless, according to private aid organization ACTED. The group based its numbers on reports from staff in the devastated area near Nahrin, 90 miles north of Kabul on the slopes of the Hindu Kush mountains.

"Each five or 10 minutes there is a shake still going on," said Shoja Zare, an ACTED radio operator in Kabul who was in contact with colleagues in Nahrin. "There is no hospital, there is no doctor to help these people."

At the scene, regional commander Gen. Aider Khan said as many as 2,000 people were missing. Many of Nahrin's residents spent the night without food or shelter because nearly all of their homes were destroyed.

Yusuf Nuristani, a spokesman for the interim Afghan administration, said the quake measured 6.2 on the Richter scale, though the U.S. Geological Survey in Golden, Colo., said it was magnitude 5.9 and centered 105 miles north of Kabul. The quake was relatively shallow, just 40 miles below the surface and capable of causing heavy damage.

By early afternoon, 600 bodies had been pulled from the wreckage of collapsed homes, Defense Ministry official Mira Jan said.

"I can say that 90 percent of Nahrin has been destroyed," Jan said. "We asked (peacekeepers) and all other humanitarian non-governmental organizations to help the people there because they lost everything. They need tents, medicines, everything."

By late afternoon, about 400 people had been wrapped in white cotton shrouds and buried in and around Nahrin — some of them in mass graves, said Nurullah, secretary of commander Haider Khan.

About 200 wounded were taken to Pul-e-Kumri and Baglan by helicopter, bus and trucks, while some 70 people were treated in Nahrin. But Gen. Khalil, a military commander from Pul-e-Kumri, said rescuers didn't have enough helicopters to transport all the wounded. Roads in the area were blocked by rubble and impassable.

"The condition is very terrible," Nurullah said by satellite telephone. "The people are in a very bad condition. ... Everyone is trying to find the members of their families to bring them out of the destroyed walls or collapsed areas. The earthquake is going on, and each time, the people are very afraid."

Interim Prime Minister Hamid Karzai canceled a trip to Turkey scheduled Wednesday to manage the disaster, Nuristani said. Officials allocated $600,000 for immediate aid, he said.

Karzai planned to visit the affected area soon, a government minister told the Afghan Islamic Press. Health Minister Dr. Suhaila Sidiq and Gen. Mostapha of the Defense Ministry had reached the quake area. Interior Minister Yunus Qanooni also planned a visit soon.

U.N. spokesman Yusuf Hassan said five villages in the quake area were destroyed. The region, which has been hard-hit by drought and food shortages, is home to an estimated 82,000 people.

Hassan said aid groups were trying to get tents and other emergency supplies to the homeless there. ACTED was providing 2,000 tents and 1,000 blankets, U.N. spokeswoman Rebecca Richards said in Kabul. The World Food Program was sending 175 U.S. tons of food to the area. U.N. spokesman Manoel de Almeida e Silva said the United Nations also was rushing emergency aid to the scene. He said preliminary reports indicated more than 200 houses were damaged around the village of Nahrin.

The Nahrin offices of ACTED, a French organization, were destroyed.

Earthquakes and seismic activity are common in this region — particularly in the Hindu Kush mountains — though they are not usually felt over such a wide area. Two strong quakes in February and May of 1998 killed nearly 10,000 people.

A 7.2-magnitude quake in the Hindu Kush mountains on March 3 killed more than 100 people. That quake was the strongest in the region since 1983, but was much deeper than Monday's — about 150 miles below the surface.

The Associated Press contributed to this report.