President Donald Trump warned on Wednesday that the United States would destroy Iranian gunboats that harass American ships at sea.
The threat, which contributed to a recovery in oil prices, came days after the Pentagon claimed that ships from Iran's Islamic Revolutionary Guard Corps Navy took "dangerous and provocative" actions near U.S. Navy and Coast Guard ships in the Persian Gulf.
"I have instructed the United States Navy to shoot down and destroy any and all Iranian gunboats if they harass our ships at sea," the president wrote in a post on Twitter.
West Texas Intermediate, the U.S. benchmark, rose more than than 30% on Wednesday after slumping to historic lows this year as the coronavirus pandemic crushed demand. Iran produced 3% of the world's oil last year.
Six U.S. military vessels were conducting training operations in international waters last week when 11 Iranian ships "crossed the bows and sterns of the U.S. vessels at extremely close range and high speeds," according to the April 15 U.S. Navy statement.
At one point, the Iranian ships came within 10 yards of the Coast Guard cutter Maui's bow.
The U.S. crews issued multiple warnings via bridge-to-bridge radio, five short blasts from the ships' horns and long-range acoustic noise devices to the Iranian ships.
"After approximately one hour, the IRGCN vessels responded to the bridge-to-bridge radio queries, then maneuvered away from the U.S. ships and opened distance between them," the statement added.
Hours after the incident, Secretary of State Mike Pompeo said the administration was evaluating a response.
"We've seen this before, where the Iranians behave in ways that were inconsistent with international law," Pompeo said.
He said the U.S. was "evaluating how best to respond and communicate our displeasure with what took place."
The latest tension comes months after the U.S. and Iran appeared to take a step back from the brink of war.
In January, the U.S. killed Iran's Gen. Qasem Soleimani, a top official in the country who the U.S. accused of orchestrating attacks on Americans.
Iran retaliated with attacks on two bases housing U.S. forces in Iraq. There were no fatalities from the strikes, but more than 100 troops have since been diagnosed with brain injuries inflicted during the attack.