"It's a tough neighbourhood, and we have to make sure we are protected," the Post quoted a senior government official in a US-allied Arab state as saying.

The official called Iran the "number one threat in the region".

US officials were quoted as saying that the willingness of other Arab states to accept the US defences reflects growing unease in the region over Iran's ambitions and capabilities.

"Our first goal is to deter the Iranians," a senior administration official told the Times.

"A second is to reassure the Arab states, so they don't feel they have to go nuclear themselves. But there is certainly an element of calming the Israelis as well."

'Interesting timing'

Riad Kahwaji, the founder of the Institute for near East and Gulf Military Analysis, said that he believed such missile batteries had actually been deployed in the Gulf during last year.

"The decision was taken over a year ago, before the end of the Bush administration," he told Al Jazeera from Dubai.

"Why they were announced now ... the timing is interesting it comes during a period where the US, along with Europe, is trying to push for a strong resolution at the UN.

"Also they come at a time there is more threats in the region ... and at a time when the US is putting more pressure on China and Russia to come on board here.

"It is more like psych-warfare against the Iranians, some sort of pressure on the other players over sanctions and a deterrant message to Iran not to do anything in reaction to any future sanctions." 

The deployments could forestall any Iranian retaliation in response to the sanctions, as well as discourage Israel from launching a military attack against Tehran's nuclear and military facilities.

Washington is seeking to win over its allies to impose a fourth set of UN sanctions on Iran that would target the Iranian Revolutionary Guards Corps, which is believed to control the military aspect of Tehran's nuclear programme.

General David Petraeus, who heads the US Central Command that oversees US military operations stretching from the Gulf to Central Asia, said the accelerated deployment of missile systems included eight Patriot missile batteries, "two in each of four countries".