The tremors, which IRNA said caused no casualties or damage, struck less than a month after a powerful earthquake devastated the ancient southeastern city of Bam and killed at least 41,000 people.

The strongest, measuring 4.8 on the Richter scale, occured at 3:14 amGMT Sunday) in the southern region of Dashti -- just 80 kilometres (50 miles) from Bushehr where the Islamic republic is building its first nuclear power plant.

Residents spent the night outside for fear of a new quake, IRNA said.

The story was similar in the central town of Shar-e Raza, near the city of Isfahan, which was shaken by a tremor with a magnitude of 4.2 just half an hour earlier.

IRNA said a third quake also measuring 4.2 hit less than two minutes later in Broujen, about 50 kilometres (30 miles) from Shahr-e Reza.

TERRA.WIRE