US warns citizens to 'exercise caution' when visiting Saudi Arabia

The US State Department on Wednesday issued a fresh travel advisory warning citizens to "exercise increased caution" when visiting Saudi Arabia.

The cautionary message comes just days after two key oil facilities in the kingdom's east were struck in attacks claimed by Yemen's Houthi rebels.

The Iran-backed Houthis have also claimed previous drone and missile strikes on Saudi airports and oil pipelines this year.

The advisory tells citizens to exercise "increased caution" while in the kingdom because of the risk of "terrorism" and the "threat of missile and drone attacks on civilian targets".

"Regional actors hostile to Saudi Arabia have conducted destructive and sometimes lethal attacks against a variety of targets including critical infrastructure, military facilities, airports, and energy facilities throughout the country, as well as vessels in Red Sea shipping lanes," the State Department note reads.

It later names Iran as one of those "regional actors", who it says has supplied the Houthis and "other regional proxy groups" with weapons.

US officials have blamed Iran for Saturday's attacks, with the latest unconfirmed reports indicating missiles and drones were launched from an Iranian based inside Iran but close to the Iraqi border.

Iran has denied a role in the attacks but President Hassan Rouhani said on Wednesday that the Houthis had targeted Saudi oil facilities as a "warning" about a possible wider war in response to the kingdom's US-backed intervention in the conflict-ravaged country.

Saudi Arabia said it would hold a press conference at 2:30pm GMT on Wednesday to disclose "material evidence and Iranian weapons proving the Iranian regime's involvement in the terrorist attack".

Yemeni border regions off limits

US embassy personnel and their families are now forbidden from using the Abha airport without Chief of Mission approval, the note added.

Abha airport, a dual civilian and military facility, is a frequent target of Houthi-claimed drone attacks.

US Mission personnel are also barred from travelling within 50 kilometres of the Yemeni border, the note added.

The exclusion zone includes the cities of Najran and Jizan, the airports of which are frequent targets of Houthi-claimed attacks.

Other US citizens are also warned not to travel within 50 kilometres of the border as the embassy has "limited ability" to provide emergency assistance.