CAIRO, Feb 24 (Reuters) - An attack by Yemen's Houthis on the freighter Rubymar caused significant damage to the ship and an 18-mile (29-km) oil slick, the U.S. military's Central Command said on Friday.

Yemen’s Houthis targeted the Rubymar in the Gulf of Aden on Sunday, and it is now at risk of sinking, the group’s military spokesperson Yahya Sarea said in a statement the following day.

"The ship is anchored but slowly taking on water," Central Command said in a statement regarding the Belize-flagged UK-owned cargo ship.

The Rubymar was transporting over 41,000 tons of fertilizer when it was attacked, the statement added.