CENTCOM said Iran struck down an Army Apache helicopter on Monday.
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.
Following the announcement of a two-week ceasefire, initial U.S.-Iran talks in Pakistan in April failed to reach a peace deal.
Trump later announced the open-ended extension of the ceasefire and the continuation of a U.S. blockade until negotiations are concluded "one way or the other."
U.S. forces have begun launching "self-defense" strikes in response to Iran's attack on a U.S. Army Apache helicopter, U.S. Central Command said.
The strikes began at 5 p.m. ET, it said.
The U.S. Apache attack helicopter that crashed near the coast of Oman overnight was brought down by an Iranian drone, two U.S. officials familiar with the Pentagon’s latest assessment tell ABC News.
The investigation has not yet determined whether Iran intended to use the drone to attack the helicopter, they added.
The drone involved in the incident is the same type Iran typically uses to target ships transiting the Strait of Hormuz, one official said.
-ABC News' Shannon K. Kingston and Luis Martinez
The autonomous surface sea drone used to rescue the two Apache crewmembers picked them up and transported them to another location on the water where they were then hoisted up to a helicopter for further transport, according to a U.S. official.
As President Donald Trump says the U.S. military believes Iran is to blame for the downing of a Apache helicopter that crashed in the Middle East, an Iranian official suggested Iran is ready to retaliate if commitments are broken.
"We prefer the language of diplomacy, but we speak other languages far more fluently. Break your commitments, and we'll switch to what we speak best. You ride the horse you saddled!" the speaker of the Iranian parliament, Mohammad Bagher Ghalibaf, said in a post on X.
