"The DCA (Defense Cooperation Agreement) will enhance military coordination between the United States and the United Arab Emirates, further advancing an already robust military, political, and economic partnership at a critical time," a joint statement said.

"The United States and the United Arab Emirates share a deep interest in promoting prosperity and stability in the region.

"The DCA will advance that interest by fostering closer collaboration on defense and security matters and supporting efforts by both nations to maintain security in the Gulf region."

US national security advisor John Bolton was in Abu Dhabi Wednesday, meeting his Emirati counterpart, Sheikh Tahnoun bin Zayed Al Nahyan.

Bolton said Iran was almost certainly behind recent oil tanker attacks that sent Gulf tensions soaring. Riyadh's regional rival Tehran dismissed the accusation as "laughable".

This came on the eve of emergency Arab and Gulf summits called by Saudi Arabia to discuss the stand-off and ways to isolate Tehran.

Two Saudi oil tankers, among four vessels, were the targets of mysterious acts of sabotage off the UAE this month, and Iran-aligned Yemeni rebels have stepped up drone attacks on the kingdom -- one of which resulted in the temporary shutdown of a major oil pipeline.

Saudi Arabia and the US have accused Iran of being the mastermind behind the Yemeni rebels' attack on the pipeline, while an investigation has been launched into the attacks on ships off the UAE.

On Friday, US President Donald Trump bypassed Congress to sell $8.1 billion in arms to Saudi Arabia and other Arab allies, citing the alleged threat from Iran.