Riyadh joined a US-led force to protect Gulf shipping as tensions with Iran soared after the September 14 attacks that temporarily knocked out half of the OPEC giant's production.

"The visit was an opportunity to discuss our mutual efforts going forward to coordinate defence against provocation and attack," said Vice Admiral Jim Malloy, commander of US Naval Forces in the Middle East, according to a statement released on Tuesday.

It added the visit focused on the Saudi navy's role in "efforts to strengthen and reinforce defences against the Iranian aggression".

Malloy met with Saudi navy commander Fahad al-Ghofaily in Riyadh on Sunday, three days after the Pentagon announced it was sending 200 troops with Patriot missiles to bolster the kingdom's defences.

The US has pushed for the creation of a US-led operation dubbed the International Maritime Security Construct to safeguard trade and the flow of oil through the Strait of Hormuz.

It has so far been joined by Australia, Britain and the United Arab Emirates, as well as Bahrain, the Gulf island state which is home to the US Fifth Fleet.

The initiative followed a number of mystery attacks on oil tankers and facilities in and around the strategic waterway through which a third of the world's seaborne oil passes.

Tensions have risen further since Saturday when twin attacks blamed by Washington and Riyadh on Tehran hit the world's largest oil processing plant and a major oilfield in Saudi Arabia.

Iran has repeatedly denied it was responsible, saying that the attacks were carried out by Yemeni rebels as they themselves have claimed.

European countries have declined to join the US-led force for fear of harming their efforts to rescue a landmark 2015 nuclear accord between Iran and major powers.