A security guard and a gunman have been killed in an exchange of gunfire in front of the US consulate in Jeddah, Saudi police said.

An armed man got out of a car in front of the consulate building on Wednesday and was killed as he exchanged gunfire with security officers, the official SPA news agency reported on Wednesday, quoting a police spokesperson.

A Nepalese security officer was wounded and later died.

Investigations are under way into the shootings.

"We offer our sincere condolences to the family and loved ones of the deceased local guards member," the State Department said in a statement in Washington.

The State Department said that Saudi forces killed the assailant and that the United States was in touch with the kingdom as it starts an investigation.

"The consulate was appropriately locked down and no Americans were harmed in the attack," it said.

"The US Embassy and Consulate remain in contact with Saudi authorities as they investigate the incident."

Previous attacks

The consulate has been targeted several times in recent years.

In 2016, a suicide bomber was killed and two people were wounded in a blast near the compound.

And in 2004, five people stormed the US consulate with bombs and guns, killing four Saudi security personnel outside and five local staff within.

Three of the attackers were killed in the assault and two were captured.

The 2004 attack in Jeddah followed other deadly bombings and shootings against expatriate compounds, Westerners working in the country and other targets.