A UH-1Y Venom helicopter with Marine Medium Tiltrotor Squadron (VMM) 163 (Reinforced), 11th Marine Expeditionary Unit (MEU), takes off from the flight deck of the amphibious assault ship USS Boxer (LHD 4) during a strait transit.
FILE - Map showing Iran and the Strait of Hormuz.

Updated at 3:56 a.m. July 19, 2019.

President Donald Trump said a U.S. warship shot down an Iranian drone Thursday that was threatening the ship and its crew in the Strait of Hormuz.

Trump told reporters at a White House event that the drone came within 900 meters of the USS Boxer and ignored "multiple calls to stand down."

"The drone was immediately destroyed," he said. "This is the latest of many provocative and hostile actions by Iran against vessels operating in international waters. The United States reserves the right to defend our personnel, our facilities and interests."

Iranian Foreign Minister Mohammad Javad Zarif said in New York that he had "no information on losing a drone today."

All of the country's drones returned to base, Iran’s top military spokesman said, the semi-official Tasnim news agency reported.

“All drones belonging to Iran in the Persian Gulf and the Strait of Hormuz ... returned safely to their bases after their mission of identification and control, and there is no report of any operational response by USS Boxer,” Abolfazl Shekarchi, a senior armed forces spokesman, was quoted as saying by Tasnim.

“We have not lost any drone in the Strait of Hormuz nor anywhere else,” tweeted Deputy Foreign Minister Abbas Araghchi.

But Trump called on all nations to condemn what he called "Iran's attempt to disrupt freedom of navigation and global commerce."

The Pentagon said in a statement the incident happened about 10 a.m. local time. "The amphibious ship USS Boxer was in international waters conducting a planned inbound transit of the Strait of Hormuz,” it said. “A fixed-wing unmanned aerial system (UAS) approached Boxer and closed within a threatening range. The ship took defensive action against the UAS to ensure the safety of the ship and its crew."

Thursday's incident is bound to increase tensions between the United States and Iran, which are already simmering over U.S. sanctions that have wrecked the Iranian economy, and the U.S. withdrawal last year from the 2015 nuclear deal that Iran had reached with global powers.

Iran has also started backing away from parts of the deal and has threatened to further increase uranium enrichment unless the European Union helps the Iranian economy.

Iran shot down a U.S. drone last month that it said was flying over its territory. The U.S. said the drone was over international waters. Trump called off a retaliatory airstrike at the last minute, saying he wanted to avoid Iranian casualties.

The U.S. also suspects Iran was behind mine attacks on several foreign oil tankers in the Gulf of Oman last month.v Iran says U.S. actions in the Middle East, including missile sales to its archrivals Saudi Arabia and the United Arab Emirates, threaten to blow up the region.