The sources said diplomatic talks were ongoing, including a planned meeting of the foreign ministers of Great Britain, France and Germany with their Iranian counterparts in Geneva on Friday.

Some sources have pointed out that it is possible that the US attack on Iran will be carried out over the weekend.

"Senior officials in several federal agencies have also begun preparing for the attack," said one source.

US President Donald Trump on Wednesday publicly discussed a possible attack on Iran, saying he has"ideas on what to do".

Hours earlier, Trump said,"Maybe I'll do it. Maybe I won't do it," when asked if an attack on Iran was imminent.

Reuters: The US is moving some military planes and ships from bases in the Middle East

The US military has moved some aircraft and ships from bases in the Middle East that could be exposed to any potential Iranian attack, two unnamed US officials told Reuters.

Officials said on Wednesday that the relocation of aircraft and ships was part of plans to protect US forces, but declined to say how many had been moved or where.

One official said aircraft that were not in fortified shelters had been moved from the Al Udeid Air Base and warships had been moved from a port in Bahrain, where the US Fifth Fleet is based.

- This is not an unusual practice - the official said, stating that the priority is the protection of American forces.

Separately, the US Embassy in Qatar issued an alert this morning temporarily restricting its personnel's access to Al Udeid Air Base, the largest US military base in the Middle East located in the desert near Doha.

The embassy told staff and American citizens in Qatar to increase caution"in light of ongoing regional hostilities."

Iran has told Washington that it will respond strongly to the United States if it becomes directly involved in Israel's military campaign, Iran's ambassador to the United Nations in Geneva said on Wednesday.

The American strike may be this weekend, and you can follow all the events from the Middle East in our live blog.

Read also why Israel attacked Iran right now and why the conflict flared up.

Who has a stronger army - Iran or Israel see in a separate text.