DUBAI, United Arab Emirates >> Drones attacked an Iranian defense factory in the central city of Isfahan overnight, the state-run IRNA news agency reported early Sunday.

It carried a Defense Ministry statement saying the attack occurred late Saturday and caused minor damage to a rooftop. The report said three drones were shot down by Iranian air defenses.

The ministry did not say who was suspected of carrying out the attack.

Separately, Iran’s state TV said a fire broke out at an oil refinery in an industrial zone near the northwestern city of Tabriz. It said the cause was not yet known, as it showed footage of firefighters trying to extinguish the blaze.

Iran and Israel have long been engaged in a shadow war that has included covert attacks on Iranian military and nuclear facilities.

Last year, Iran said an engineer was killed and another employee was wounded in an unexplained incident at the Parchin military and weapons development base east of the capital, Tehran. The ministry called it an accident, without providing further details.

Parchin is home to a military base where the International Atomic Energy Agency has said it suspected Iran conducted tests of explosive triggers that could be used in nuclear weapons.

In April 2021, Iran blamed Israel for an attack on its underground Natanz nuclear facility that damaged its centrifuges.

Israel has not claimed responsibility for the attack, but Israeli media widely reported that the country had orchestrated a devastating cyberattack that caused a blackout at the nuclear facility. Israeli officials rarely acknowledge operations carried out by the country’s secret military units or its Mossad intelligence agency.

In 2020, Iran blamed Israel for a sophisticated attack that killed its top nuclear scientist.

Iran has always insisted its nuclear program is for purely peaceful purposes. U.S. intelligence agencies, Western nations and the International Atomic Energy Agency have said Iran ran an organized nuclear weapons program until 2003.

The United Nations’ top nuclear official, Rafael Mariano Grossi, recently warned that Iran has enough highly enriched uranium to build “several” nuclear weapons if it chooses.

Efforts to revive a 2015 agreement with world powers that placed limits on Iran’s nuclear activities ground to a halt last year. Both the U.S. and Israel have vowed to prevent Iran from ever acquiring nuclear weapons, and neither has ruled out military action.