"A residential building was targeted in the centre of Tehran, killing five people," the broadcaster said.

It added the death toll may rise as the strike hit a densely populated area in central Tehran.

Powerful explosions rocked the area at least twice, minutes apart, sending clouds of heavy black smoke into the sky, said an AFP journalist at the scene.

Crowds of people rushed to the site of the blast near the communications ministry, the journalist said.

The attack occurred amid an intense exchange of fire between Iran and Israel.

On Friday, Israel launched an attack that has killed top military commanders and nuclear scientists, and struck military bases, nuclear sites and residential areas across the country.

Iranian media has said the death toll from Israeli attacks on Friday and Saturday was at least 128, including women and children, reporting that some 900 others were wounded.

Iran has also unleashed a barrage of missile strikes on Israel, leaving at least 10 Israelis dead overnight Saturday-Sunday and dozens more wounded.