Riyadh: Secretary of State Rex Tillerson warned global companies that they do business with Iran’s Revolutionary Guards “at their own risk,” remarks that will add to investment uncertainty in a country eager to reap the economic benefits of a 2015 nuclear accord.

Tillerson’s Saudi visit Sunday aimed to inaugurate an alliance against Iran between the kingdom and Iraq, called on governments to join a US sanctions regime against the Islamic Revolutionary Guard Corps, a hard-line military and political force.

“Both of our countries believe that those who conduct business with the Iranian Revolutionary Guard, any of their entities - European companies or other companies around the globe “” really do so at great risk,” Tillerson said at a briefing with Saudi Foreign Minister Adel Al Jubeir.

The Revolutionary Guards “foment instability in the region and create destruction in the region,” Tillerson said.

His sanctions comments signaled that the administration, while leaving the landmark 2015 accord intact for now, will increase economic pressure by other means to punish Iran for its alleged sponsorship of terrorism and development of ballistic missiles.President Donald Trump announced a new Iran strategy Oct. 13, refusing to certify the 2015 deal between the Islamic Republic and world powers. But instead of repudiating the deal, he asked Congress to change it to to ensure it counters Iranian political influence in the Middle East and announced more sanctions on the IRGC.

In turn, the US wants European allies - the UK, France and Germany - to get on board with strengthening the nuclear accord and extend some restrictions that are set to expire in 2025. The comments appear to be aimed at forcing US allies to make a choice: Do business with Iran, with its economy of $393 billion, or the $19 trillion US economy.

The US Treasury Department has designated the IRGC as a supporter of terrorism for its backing of the Quds Force, which conducts operations outside Iran. Iran has frequently argued that it isn’t seeing economic benefit from sanctions relief it was granted under the nuclear agreement, and Tillerson’s comments may only exacerbate that concern.

Many businesses, including Boeing Co., Airbus SE and General Electric Co., have ventured into Iran. Boeing is scheduled to begin initial deliveries next year for the first of 80 aircraft ordered by Iran Air under a deal valued at $16.6 billion before customary discounts. Boeing is still completing licensing for a $3 billion pact with Iran Aseman Airlines.