The Israeli army says 200 jets struck more than 100 sites across Iran in a large-scale attack. Israel’s military says it launched a wave of strikes on Iran, hitting key nuclear facilities and killing senior Iranian commanders and nuclear scientists in a major attack.

WASHINGTON (AP) — President Donald Trump says an Israeli attack on Iran over Tehran’s nuclear program is not imminent but “could very well happen.” “I don’t want to say imminent, but it looks like it’s something that could very well happen,” Trump told reporters at the White House on Thursday.

"We have taken note with great concern of the various statements concerning a considerable increase in enrichment capacity, and in particular, the establishment of new infrastructure."

Here is a timeline tracing key developments in Iran’s nuclear programme over the years. The United States and Iran, then ruled by Shah Mohammad Reza Pahlavi, who was brought to power by a 1953 CIA coup against the country's democratically-elected Prime Minister Mohammad Mosaddegh, sign an agreement on civil nuclear cooperation.

Tehran said American bases in the Middle East could face reprisals if the U.S. helped repel Iranian attacks on Israel.

The reaction was noticeably different on Friday than it was after the last time Israel attacked Iran, when several countries provided backup and resources.