Oil prices hit a six-week high on Monday, nearing $100 a barrel.
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israeli strikes targeting military, government and infrastructure sites.
Delegations from the U.S. and Iran entered negotiations in June aimed at a war-ending deal based on a memorandum of understanding signed by both countries.
The U.S. and Iran have nonetheless continued to exchange strikes, with the strategic Strait of Hormuz as the primary flashpoint. Trump said in August that the U.S. would launch a "crushing economic operation" to force Tehran into submission.
U.S. forces "struck multiple Iranian tankers tied to the IRGC in response to more attempted missile attacks on a U.S. Navy warship," a U.S. official confirmed to ABC News.
-ABC News' Luis Martinez and Steve Beynon
An additional 30 troops have been wounded in the war with Iran, according to the Pentagon's casualty database.
As of Tuesday, 820 U.S. troops have been wounded and 18 have been killed.
-ABC News' Steve Beynon
Iran's Islamic Revolutionary Guard Corps issued a warning that all oil tankers in Kuwaiti and Bahrani waters be evacuated after an alleged U.S. attack on an Iranian oil tanker.
"In light of the atrocities committed by the terrorist US army in targeting several tankers of the Islamic Republic of Iran, we warn all tanker crews in the Kuwaiti and Bahraini ports, which host these terrorists and are partners in their atrocities, to immediately abandon their vessels, whether at anchor or at the ports, because they will be targeted," Iran's IRGC Navy said in a statement Tuesday.
Iran state media claimed the U.S. attacked an oil tanker near Kharg Island on Tuesday.
According to a report from Tasnim News Agency, a small Iranian oil tanker, located 4 nautical miles from Kharg Island, was the target of a missile attack by the U.S. military.
The tanker was struck by a projectile fired by U.S. forces in the vicinity of Kharg Island's anchorage, Tasnim said.
Tasnim said there are no reported casualties.
-ABC News' Desiree Adib
