Tanker operators don’t expect their ships to be targeted in the near term amid the growing tensions between the U.S. and Iran as daily freight and insurance rates hold steady in a critical region for global oil transport. “The Middle East is like a powder keg, but we don’t expect any attacks on tankers, at least for now,” said an executive at a Europe-based operator of more than two dozen tankers. “We’ve had some verbal assurances [from Iran] that ships won’t be hit, so we keep our fingers crossed.”

Iran’s Islamic Revolutionary Guards Corps attacked or seized a series of tankers last spring as Tehran began to push back against U.S. sanctions imposed after President Trump withdrew the U.S. from a 2015 international nuclear agreement. Ship insurers have already paid out more than $100 million in compensation over last year’s attacks, and the killing last week of Iranian military leader Maj. Gen. Qassem Soleimani in an American drone attack in Iraq raised fears that oil transport would again be disrupted as Tehran promised to retaliate.

Washington on Tuesday warned about “the possibility of Iranian action against U.S. maritime interests” in the Middle East. “U.S. commercial vessels are advised to exercise caution and coordinate vessel voyage planning for transits of the Persian Gulf and nearby waterways,” the U.S. Maritime Administration said in a statement on its website.

U.K. Defense Secretary Ben Wallace said over the weekend that two warships will be deployed in the Strait of Hormuz to prevent attacks on British-flagged tankers. Other countries, including the U.S., sent naval escorts last year. Some 20% of the world’s oil supply passes on tankers through the Strait of Hormuz, the narrow passage between the Persian Gulf and the Indian Ocean.