Three Egyptian fishermen were killed when a mine laid by Yemen's Houthi rebels struck their boat in the Red Sea, the Arab Coalition said on Friday.
Col Turki Al Malki, spokesman for the Saudi-led alliance supporting Yemen's government, said three other fishermen aboard the boat were rescued by coalition naval forces.
The boat was struck at 2am on Wednesday while in international waters, Col Al Malki said.
He said mines planted by the Iran-backed rebels posed a serious threat to maritime navigation and international trade in the southern Red Sea and Bab Al Mandeb – the narrow waterway between Yemen and Djibouti. International shipping must pass through the strait en route to or from the Egypt's Suez Canal.
Col Al Malki said the coalition had found and neutralised 137 mines planted by the Houthis.
The coalition has also intercepted "drone boats" packed with explosives that the rebels have used to target naval vessels and shipping.
Britain's naval chief, Admiral Sir Philip Jones, noted last year that the Houthis' "increased use of practical but unconventional technology such as remote-controlled and autonomous surface craft is a particular concern to global mariners”.