The U.S. Navy sunk three of four small boats from the Iran-backed Houthi rebels and killed its crews on Sunday after an attack on a Maersk container ship in the Red Sea.

Why it matters: This is the most significant engagement by U.S. forces against the Iranian-backed Houthis since they started attacking ships in the Red Sea after the Gaza war began, Axios' Barak Ravid reports.

Zoom in: There was no damage to U.S. personnel or equipment, U.S. Central Command said in a statement on Sunday.

• The small boats had "fired crew served and small arms weapons" at the Singapore-flagged Maersk Hangzhou and had gotten "within 20 meters of the vessel" and tried to board it, according to CENTCOM.
• A security team on the Maersk ship returned fire, and U.S. Navy helicopters stepped in to respond to the distress call.
• After the Houthi boats "fired upon the U.S. helicopters with crew served weapons and small arms," the U.S. Navy "returned fire in self-defense," sinking three vessels. CENTCOM said the fourth boat fled the area.

The Maersk ship had issued two distress calls in less than a day to report attacks by the Houthi boats.

• The container ship reported being struck by a missile while moving about the Red Sea, per a statement from U.S. Central Command on Saturday.
• While responding, the USS Gravely "shot down two anti-ship ballistic missiles fired from Houthi-controlled areas in Yemen toward the ships," per CENTCOM.

The big picture: The Houthis claim their attacks are against ships heading to and from Israel. But the rebels have attacked many other ships, and significantly hampered freedom of navigation on one of the world's most vital maritime commercial routes.

• Maersk, a global shipping giant with 700+ container vessels, announced Sunday that it's pausing all sailing through the Red Sea for 48 hours.

Go deeper: Maersk schedules more than 50 ships to travel via Suez Canal