A 5.1 magnitude earthquake hit at 5 AM local time on Friday less than 30 miles from the 1,000-megawatt Bushehr nuclear power plant, Iran’s only operating nuclear power plant located on the southwest Gulf coast. There were no immediate reports of damage to the reactor. The US Geological Survey said the quake struck 27 miles from the southwestern city of Borazjan and at a depth of 23 miles.

Construction of the nuclear power plant, the first civilian reactor in the Middle East, was carried out by German companies and completed in 1975 by the Russian Ministry for Atomic Energy. The nuclear fuel was provided by Russia.

In November 2014 Iran and Russia signed an agreement to build two new 1,000-megawatt nuclear reactors at the Bushehr site, with an option of six more at other sites later. Construction formally started in March 2017 and is expected to take 10 years.

Iran claims its nuclear program is peace-oriented but recently announced it has exceeded guidelines established in the Joint Comprehensive Plan of Action, known commonly as the Iran nuclear deal or Iran deal, signed with former President Barack Obama in 2015.

Iran is in a seismically active region. In November 2017 a 7.3-magnitude tremor in the western province of Kermanshah killed 620 people. In 2003, a 6.6-magnitude quake in southeast Iran decimated the ancient mud-brick city of Bam and killed at least 31,000 people. It did not damage the nearby plant. Iran’s deadliest quake was a 7.4-magnitude tremor in 1990 that killed 40,000 people in northern Iran, injured 300,000 and left half a million homeless.