KABUL, Afghanistan (CNN) -- As many as 5,000 people are feared dead after a powerful earthquake struck remote northern Afghanistan, destroying numerous villages and leaving thousands of residents homeless, authorities said.

The mountainous region on Afghanistan's border with Tajikistan is held by forces opposed to the Muslim Taliban militia that controls most of the country.

"We need help desperately. Thousands of people are dead," said Shamshul Haq Arianfar, a spokesman for the anti-Taliban alliance.

Arianfar said at least eight villages were completely wiped out. Speaking from Chaib, he said opposition soldiers had pulled 1,650 bodies from the debris.

"We have to tell the people to leave the area . . . it is too dangerous," Arianfar said.

Opposition spokesman Abdullah Abdullah said the death toll could rise.

"The number of casualties according to a report I just got from the ministry of security is more than 5,000 dead and more than 1,000 injured. That is just the bodies recovered," the minister, who is visiting London, told the British Broadcasting Corporation. "We expect the numbers will rise," he said.

A press officer with the International Committee of the Red Cross said aid workers could not confirm the reports until they had checked the region. Helicopters were on their way to the stricken areas, and planes were due to depart from Pakistan to the region to carry relief aid to the victims.

Saturday's powerful quake rocked the same region where several thousand people were killed in a February quake that launched an international rescue operation.

"We heard through the authorities in the North that at least 15 to 20 villages have been destroyed," the ICRC's Juan Martinez said. He said he had been told by officials in the North that about 3,000 people were dead.

Based on the magnitude and destruction of the February quake, Martinez said, "This figure is possible. (Saturday's quake) seems to be at least of the same intensity, and that is why we are trying to send as much medical material as we can."

Other aid workers were skeptical of the extent of the damage. "The quake happened in the daytime, when most people were outside and not in their houses," one aid worker said. "Or they may have been living in tents while bringing in the harvest, so these figures may be highly exaggerated."

Estimates of the quake's strength also varied. Pakistani seismologists reported three quakes between magnitudes 4.5 and 5.4, and Beijing's seismological office put the strength of the quake at 7.1. The U.S. Geological Survey estimated the quake's magnitude at 6.9, compared to February's magnitude 6.4 quake.

The quake struck the Rustaq region near the border with Tadjikistan, about 150 miles (240 km) north of the Afghan capital of Kabul, the same area as in February, according to Jacques Trembley of the medical relief group Doctors Without Borders. "We felt it here; it was strong," Trembley told Reuters via telephone from the northern town of Mazar-i-Sharif.

Martinez said heavy rains were impeding the flow of relief supplies and personnel into the area and that planes of relief supplies were being diverted from Kabul to the Pakistani city of Faisalbad.

Aid agencies have remained in northern Afghanistan since the February quake trying to coordinate and distribute relief in an area where thousands of homes were flattened and thousands left homeless.

"This time, at least, we have some NGOs (non-governmental organizations) on the spot who stayed there after the first earthquake," Martinez said.

Another aid worker added: "There is infrastructure there if this turns out to be another major disaster, but as of this moment we do not know and will not be sounding the alarm bells."

Reuters contributed to this report.