Airlines cleared out of the airspace over Israel, Iran, Iraq and Jordan on Friday after Israel launched attacks on targets in Iran, Flightradar24 data showed, with carriers scrambling to divert and cancel flights to keep passengers and crew safe.

Tel Aviv's Ben Gurion Airport was closed until further notice, and Israel's air defence units stood at high alert for possible retaliatory strikes from Iran.

Israeli flag carrier El Al Airlines said it had suspended flights to and from Israel.

Iranian airspace has been closed until further notice, according to state media and notices to pilots.

As reports of strikes on Iran emerged, a number of commercial flights by airlines including Dubai's Emirates, Lufthansa and Air India were flying over Iran.

Air India, which overflies Iran for its Europe and North American flights, said several flights were being diverted or returned to their origin, including ones from New York, Vancouver, Chicago and London.

Emirates and Lufthansa did not immediately respond to requests for comment.

Iraq early on Friday closed its airspace and suspended all traffic at its airports, Iraqi state media reported.

Eastern Iraq near the border with Iran contains one of the world's busiest air corridors, with dozens of flights crossing between Europe and the Gulf, many on routes from Asia to Europe, at any one moment.

Flights steadily diverted over central Asia or Saudi Arabia, flight tracking data showed.

Jordan, which sits between Israel and Iraq, closed its airspace several hours after the Israeli campaign began.

"The situation is still emerging – operators should use a high degree of caution in the region at this time," according to Safe Airspace, a website run by Opsgroup, a membership-based organisation that shares flight-risk information.

Several flights due to land in Dubai were diverted early on Friday. An Emirates flight from Manchester to Dubai was diverted to Istanbul and a flydubai flight from Belgrade diverted to Yerevan, Armenia.

Budget carrier flydubai said it had suspended flights to Amman, Beirut, Damascus, Iran and Israel and a number of other flights had been cancelled, rerouted or returned to their departure airports.

Qatar Airways cancelled its two scheduled flights to Damascus on Friday, Flightradar24 data shows.

Airspace in the Middle East last year was crossed daily by 1,400 flights to and from Europe, Eurocontrol data show. (Reuters)