ISLAMABAD, Pakistan (CNN) - A deadly 7.7-magnitude earthquake struck southern Pakistan on Tuesday, the U.S. Geological Survey said.
The death toll rose quickly, with at least 40 deaths reported in the quake's aftermath in Awaran in Balochistan province, a military official said.
In addition to the fatalities, "dozens have been injured," said Asad Gilani, the province's home secretary.
Officials fear people are trapped in the rubble. The province declared a rescue emergency. All officials were put on high alert, and doctors at hospitals were on standby.
More than 200 troops have been sent to the area to provide aid, including rescue teams and medical teams, Lt. Col. Abid Ali Askari said.
The earthquake occurred in a remote area, said Zahid Rafi, principal seismologist of the National Seismic Monitoring Center.
With a depth of about nine miles (about 15 kilometers), the quake struck 43 miles (69 kilometers) northeast of Awaran and 71 miles (114 kilometers) northwest of Bela, the USGS said.
Some mud-walled homes fell in Awaran, said Latif Kakar, director of the Provincial Disaster Management Authority in Balochistan.
The tremors lasted two minutes. People flocked out onto the streets of Quetta, the provincial capital. Aftershocks could be felt in Karachi, hundreds of miles to the southeast.
The quake was strong enough to cause a mass 30 to 40 feet high to emerge from the ocean like a small mountain island off the coast of Gwadar, local police official Mozzam Jah said. A large number of people gathered to view the newly formed island, he said.
Zahid Rafi, principal seismologist of the National Seismic Monitoring Center, confirmed the island had. He said that this is "not surprising" considering the magnitude of the earthquake.