He warned that the toll might rise and said the agency was still trying to get information from the stricken area.
"We all ran out for safety in the open field in front of our house. Many other neighbors were also there. Thank God no one was hurt in our area, but the walls of four or five houses collapsed," said Khair Mohammed Baluch, who lives in the town of Awaran, roughly 50 kilometers (30 miles) south of the epicenter.
Pakistan's chief meteorologist and the U.S. Geological Survey put the magnitude of the quake at 7.7.
Pakistani officials were investigating whether the earthquake was so powerful that it pushed up the earth and formed a new land mass.
Witnesses reported seeing a small island appear off the coast of the port of Gwadar after the quake, said the director general of the Pakistan Meteorological Department, Arif Mahmood.
Gwadar Police Chief Pervez Umrani said people gathered on the beach to see the land mass, which was about 9 meters (30 feet) high and 100 meters (109 yards) long.
Baluchistan is Pakistan's largest province but also the least populated and most impoverished. Awaran district has about 300,000 residents.
Many residents are believed to be involved in smuggling fuel from Iran, while others harvest dates.
The area where the quake struck is at the center of an insurgency that Baluch separatists have been waging against the Pakistani government for years. The separatists regularly attack Pakistani troops and symbols of the state, such as infrastructure projects.
A Pakistani military official speaking on customary condition of anonymity said security officials were fired on while escorting doctors to Awaran. No one was wounded.
The quake was felt as far as New Delhi, the Indian capital, some 1,200 kilometers (about 740 miles) away, but no damage or injuries were immediately reported there.
The quake also jolted Pakistan's largest city, Karachi, roughly 250 kilometers (155 miles) from the epicenter. People in the city's tall office buildings rushed into the streets, and Pakistani television showed lights swaying as the earth shook.
"My table and computer started shaking. I thought I was feeling dizziness but soon realized they were tremors," Karachi resident Mohammad Taimur said.
In Quetta, the capital of Baluchistan, cellphone vendor Matiullah Khan said he was in his shop with a customer when the cabinet and shelves started to shake.
"I along with customers rushed out to the main street. ... Thousands of people were standing, many in fear and reciting Quranic verses," he said.
Baluchistan and neighboring Iran are prone to earthquakes. A magnitude-7.8 quake centered just across the border in Iran killed at least 35 people in Pakistan last April.
Santana reported from Islamabad. Associated Press writers Zarar Khan and Munir Ahmed in Islamabad, Adil Jawad in Karachi, and Ashok Sharma in New Delhi contributed to this report.