The US and Saudi Arabia have been put on high alert following warnings of a potential attack from Iran.
Intelligence shared with the US warns of imminent attacks on targets in Saudi Arabia and has put the American military and other neighbouring states in the Middle East on alert, Saudi and U.S. officials said on Tuesday.
Officials have not provided any further details other than the change to the alert level.
The intelligence from Saudi officials reveals that Iran is poised to carry out attacks within the kingdom and in Erbil, Iraq - where American troops are based - to distract from the protests that have gripped international headlines, The Wall Street Journal reports.
The White House National Security Council said it was concerned and it is ready to respond if necessary.
A National Security Council spokesperson: "We are concerned about the threat picture, and we remain in constant contact through military and intelligence channels with the Saudis.
“We will not hesitate to act in the defence of our interests and partners in the region.”
Iran has already launched dozens of ballistic missiles and armed drones in northern Iraq since late September.
One of those drones, which was headed to Ebril, was shot down by a US warplane.
Iran has blamed Iranian Kurdish separatist groups in the region, Saudi Arabia, the US and Isreal for stoking the demonstrations.
It comes after the head of Iran's powerful Revolutionary Guards warned protesters that Saturday would be their last day of taking to the streets.
The threat is a sign that security forces could be planning to intensify their fierce crackdown on unrest sweeping the country.
Iran has been gripped by protests since the death of 22-year-old Kurdish woman Mahsa Amini in the custody of the morality police last month, posing one of the boldest challenges to the clerical leadership since the 1979 revolution.
"Do not come to the streets! Today is the last day of the riots," Guards commander Hossein Salami said in some of the toughest language used in the crisis, which Iran's clerical leadership blames on its foreign enemies including Israel and the United States.
"This sinister plan is a plan hatched ... in the White House and the Zionist regime," Salami said.
Iranians have defied such warnings throughout the popular revolt in which women have played a prominent role. There were more reports of fresh bloodshed on Saturday.
