TEHRAN - At least five people were killed in an earthquake of 6.5 magnitude that jolted southeastern Iran on Monday, damaging buildings in outlying mountainous areas, the region's governor said.

"So far five people have been killed. A higher number of casualties is possible because of the vast scale of the damage," said Esmail Najjar, governor of Iran's Kerman province, centre of the quake.

State television said at least three villages had been destroyed. "Hundreds of people are trapped under the rubble," the semi-official Mehr news agency quoted a local official as saying.

The US Geological Survey put the quake's magnitude at 6.3. The official IRNA news agency said nine aftershocks had hit  since the main quake, including one of 5 magnitude. Telephone lines had been cut.

Mohammad Javad Kamyab, an employee of Kerman province governor's office, said there were 30 villages in the quake-hit area.

"These villages are not heavily populated...We are not expecting a high death toll and so far 25 people have been injured," he said.

Another local official said access to the damaged villages "was very difficult".

"Rescue teams have been dispatched to the quake-hit area ... and are communicating via walkie-talkies," Hossein Baqeri, head of Iran's National Crisis Management unit, told state television.

The semi-official Fars news agency said the quake was also felt in the southeastern province of Sistan-Baluchestan, which borders Afghanistan and Pakistan.

"Many people left their houses in the city of Zahedan ... It was also felt in the towns of Bam, Khash and Iranshahr," Fars reported.

Ali Reza, a resident of Bam, told Reuters by telephone: "There was no damage in the city of Bam but we felt the quake."

The province of Kerman is highly prone to earthquakes. Some 31,000 people were killed when an earthquake razed Bam in 2003.

Kerman is not one of the oil-producing regions of Iran, the world's fourth-biggest crude exporter. Iran is criss-crossed by major faultlines and is frequently hit by earthquakes.

In 2008 a magnitude 6.1 quake struck the southern port of Bandar Abbas, killing at least seven people and injuring 40.

An official in the governor's office of Kerman province told Reuters by telephone: "The quake-hit area is a deserted area."

State television, quoting an unnamed local Red Crescent official, said: "In some rural parts of the region ... the quake has caused heavy damage to buildings, especially in Hosseinabad village, where the houses were made of earthen bricks."