An Israeli citizen has been arrested on suspicion of being involved in a plot by Iran to assassinate Prime Minister Benjamin Netanyahu and other top officials, Israel's security services say.

Israeli police and domestic intelligence said the man was twice smuggled into Iran and received payment to carry out missions.

In a joint statement, they said the suspect was a businessman who had lived in Turkey and had Turkish contacts who had helped get him into Iran.

The statement said the suspect, who was not identified, was arrested last month.

It said his targets were the prime minister, the defense minister, and the head of Israel's internal security agency Shin Bet.

It said that in April and May, the suspect twice traveled to Samandag in Turkey to meet a wealthy Iranian businessman called Eddie and was helped by two Turkish citizens.

The statement said Eddie had problems leaving Iran on both occasions, so the Israeli citizen was smuggled from Turkey into Iran instead.

It said that the man met both Eddie and 'an Iranian security operative' there.

It said Eddie asked the Israeli to 'carry out various security missions within Israel for the Iranian regime'.

According to the statement, these included transferring money or a gun, photographing crowded places in Israel and sending them to 'Iranian elements', and threatening other Israeli citizens who had been recruited by Iran but had not completed their tasks.

More than 20 people, including some children, have been killed after pagers and walkie-talkies exploded, Lebanon says.