U.S. media reported, citing unnamed U.S. officials, that Israel carried out a missile attack on Iranian territory before dawn on Friday local time.

Reports from ABC, CBS and NPR did not provide further details about the location or targets of the apparent missile strike.

An Israeli military spokesman told VOA he had no comment “at this time” on the U.S. media reports, about an hour after the report was published.

Iran’s state news agency IRNA said the Islamic Republic’s air defense systems had been activated over several provinces.

Both the Islamic Republic News Agency and Fars News Agency, the state news agency affiliated with Iran’s Islamic Revolutionary Guard Corps, reported an explosion in the central Iranian province of Isfahan, citing unnamed sources.

Fars located the location of the explosion in the city of Kaja Verestan on the eastern outskirts of Isfahan.

Israel has warned Iran that it will retaliate against Iran for its unprecedented air strikes on Israeli territory last Sunday. Iran warned that any retaliatory strikes by Israel would be met with a swift and tougher response.