LONDON (Reuters, AFP) - A magnitude 6.1 earthquake struck 76 km east-southeast of the city of Mashhad in north-eastern Iran on Tuesday, the US Geological Survey (USGS) said.

USGS said the quake occurred 76 km east-southeast of the city and at a depth of 33 km.

Iranian state television said the quake happened at 10:40am local time (2:10pm Singapore time) and had shaken Mashhad and cities around it. Tasnim news agency reported that phone lines in parts of affected areas were disrupted.

"It was horrible. It made a lot of noise. Everything was shaking," a Mashhad resident told AFP by phone.

There were no immediate reports of casualties.

Iran lies on a major fault line and sees frequent earthquakes. A 2003 quake killed at least 31,000 people and all but destroyed the historic city of Bam in the southeast of the country.