The US State Department has issued a travel warning for all of Jordan because of "threats from terrorist groups" after recent deadly attacks.
It said so-called Islamic State (IS) and its affiliates "continue to plot assaults" in the country.
More than a dozen people, including a Canadian tourist, have been killed in attacks in Jordan since last week.
The department also warned of similar threats to US citizens in Egypt, after a series of attacks there.
It advised avoiding travel to the Sinai Peninsula and the Western Desert regions.
In a statement on Friday, the department said that "terrorist and extremist organisations have expressed a desire to conduct attacks targeting US citizens and Westerners in Jordan".
"Within the last year, Jordanian authorities have notified the US Embassy of several disrupted terrorist plots targeting US citizens and Westerners," the travel warning added.
Jordan is seen by the US as a key regional player in battling IS fighters.
The jihadist group said it was behind last Sunday's attack in the central town of Karak - the deadliest assault in recent days.
Seven members of the Jordanian security forces, two local bystanders and a Canadian tourist were killed in the attack.
It began when a police patrol received reports of a fire in the village of Qatraneh, about 32km (20 miles) east of Karak.
Officers who responded came under fire from inside the house. Two were wounded before the assailants fled in a car towards Karak castle, a major tourist attraction that dominates the town.
The stand-off there lasted several hours.