TEHRAN, Iran—An explosion shook the area near Iran’s main nuclear-enrichment plant late on Saturday, prompting conflicting explanations from Iranian officials as Tehran engages in talks with world powers over its nuclear program.

The blast was heard in the area of Badroud, around 12 miles from the Natanz nuclear site, according to IRNA, Iran’s state news agency. The incident involved a sound and then a flash of light in the sky, reported Fars News Agency, an organization close to the Islamic Revolutionary Guard Corps.