A U.S. Army Apache attack helicopter crashed near the Strait of Hormuz, with President Donald Trump saying the two crew members abroad were “fine” after the incident involving the strategic waterway, which remains under a chokehold by Iran.

What caused the crash remained unclear Tuesday morning in the Middle East, which was still reeling after Iran and Israel exchanged fire the previous day in the biggest blow yet to the straining ceasefire in the Iran war. Iranian state media, relying on foreign reporting, acknowledged the crash without elaborating.

Since the U.S. and Israel began striking Iran on Feb. 28, the war has shaken the global economy, driven up energy prices around the world and made many basics, including food, more expensive. Officials have been unable to turn the April ceasefire into a deal to permanently end the conflict.

Trump, speaking to journalists at John F. Kennedy International Airport in New York after watching the NBA Finals on Monday night, acknowledged the crash.

“The pilots are fine. Yeah,” Trump said. “Nobody injured. We are going to issue a report tomorrow. But the pilots are fine.”

The New York Times first reported that a U.S. Army Apache attack helicopter went down near the strait in unclear circumstances. The U.S. military's Central Command and the Defense Department did not immediately respond to requests for comment from The Associated Press.

Apache helicopters have been a key asset for the American military as it enforces a blockade on Iranian crude oil shipments and tankers, seeking to pressure Tehran into reaching a deal. The helicopters also have been used by the United Arab Emirates to shoot down Iranian drones during the Iran war.