The United States and Israel have launched an attack on Iran, with explosions heard and seen across Tehran.

Several missiles have struck University Street and the Jomhouri area in Tehran, Fars news agency reported. Smoke was seen rising in the city, according to an Al Jazeera correspondent on the ground.

Iran’s semi-official Tasnim news agency reported that explosions also occurred in Tehran’s northern Seyyed Khandan area. Other Iranian media cited attacks nationwide.

Israel’s Defence Minister Israel Katz claimed Israel launched the missile attack in order to “remove threats to the State of Israel”.

A United States official told Al Jazeera that the attacks were carried out as a joint military operation between Israel and the US, which has assembled a vast fleet of fighter jets and warships in the region to try to pressure Iran into a deal over its nuclear programme.

The Associated Press news agency reported that the strike in Iran’s capital happened near offices of Supreme Leader Ayatollah Ali Khamenei. According to an official cited by Reuters, Khamenei is not in Tehran and has been transferred to a secure location.

Al Jazeera’s Maziar Motamedi, reporting from Tehran, said cellphone communications has been disrupted in several areas of the capital. “No calls are possible at present,” he said.