In the White House, Trump said the drone threatened "the safety of the ship and the ship's crew" in the Strait of Hormuz and was "immediately destroyed".
The drone was reportedly destroyed by electronic disruption as a US Defense official.
The Boxer crew took defensive action after the drone was at a threatening distance from the US ship.
"This is the last of Iran's many provocative and hostile actions against ships operating in international waters," added Trump. "The United States reserves the right to defend our personnel, facilities and interests, and urges all nations to condemn Iran's attempts to disrupt maritime freedom and global trade." own ships.
Relations between Iran and the United States have deteriorated since May 201
The Pentagon released a statement shortly after Trump's comments on the drone's launch.
"At about 10 am local time, the amphibious USS Boxer was in international waters, conducting a scheduled inbound transit through the Strait of Hormuz An unmanned fixed wing (UAS) approached Boxer and closed within an impending range took defensive action against the UAS ensuring the safety of the ship and its crew, "wrote Pentagon spokesman Jonathan Hoffman.
"We rate the UAS as Iranian," said Pentagon spokeswoman Cdr. Rebecca Rebarich told CNN.
A US military official told CNN that Marines aboard the USS Boxer had used the counter-drone jamming equipment and shot down the suspicious Iranian drone.
The Iranian Revolutionary Guard said at the time that it had launched a "penetrating American spy drone" after it entered the country's territory. A US official confirmed to CNN that a drone had been shot down, but said the incident occurred in international airspace over the Strait of Hormuz, one of the world's most important shipping routes.
On Thursday, Trump said that "Iran is a lot. At the moment I added a country other than when I took it over," adding that the country was the "scourge of the world" at the time of its inauguration.
And on Tuesday, the US president said "a lot of progress" was made with Tehran.
"They would like to talk and we'll see what happens, but great progress has been made," he said.