US warns its citizens in Jeddah of 'imminent threat'

Without giving further details on the reported threat, the US State Department urged Americans to reconsider non-essential travel plans within Saudi Arabia.

In a security message published online, the State Department said it had "received reports of a potential, imminent threat against US citizens in areas of Jeddah frequented by Westerners, such as markets, restaurants and shopping malls, among others."

The message reiterated existing guidance for visitors to Saudi Arabia.

"Remember to vary your routes and times in all instances when traveling in the Kingdom," the notice said.

"All US citizens are encouraged to be aware of their surroundings, and take extra precautions when travelling throughout the country," it added.

At a news briefing in Washington on Thursday, State Department spokesman John Kirby said the "information just recently became available to us."

He told reporters the threat was "credible enough and specific enough" that it warranted an immediate security message.

Saudi Arabia was targeted by three bomb attacks earlier this month, including one in Jeddah, the kingdom's second city and major Red Sea port.

CIA director John Brennan said the attack bore hallmarks of the Islamic State [IS] group.

Regional heavyweight Saudi Arabia is part of the US-led international coalition battling IS in Iraq and Syria.

Since March 2015, the country has also led a coalition fighting Iran-backed rebels in Yemen.

In the past year, Saudi authorities have stepped up the arrests of radical Islamists and in 2015 announced that they had dismantled an IS-linked group, detaining hundreds of suspects, mostly Saudis.

Agencies contributed to this report.