Rumor has it, several members of the Royal Saudi family were on board, and either killed or heavily injured. But then, that family meanwhile has about 100,000 members...

US officials are talking about 'four shoulder-launched rockets, provided by Iran:
The U.S. Navy dispatched three warships near the southern coast of Yemen after four rockets hit and nearly sank a United Arab Emirates auxiliary ship Saturday, two U.S. defense officials told Fox News.

Iran-backed Houthi rebels in Yemen claimed responsibility for the attack. There were no reported injuries to the Emerati crew. Al Jazeera reported on video of the attack.

Iran supplied the Houthis with the “shoulder-fired rockets” that nearly destroyed the UAE ship, according to two U.S. officials. It was not immediately clear what type of rocket the rebels may have fired.

The ship was formerly contracted to the U.S., two defense officials confirmed, and at one time an American company owned the vessel.
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...but photos are clearly showing only one 'entry hole' - with possibility of there being another one, on the port side of the ship.

What's making no sense to me: a radar-guided weapon like C.701 or C.802 would go for either the centre of the ship, or the point with highest RCS, while Swift was hit at the bow.

Another 'problem' is that Swift was made of aluminium, and aluminium is relatively easy to set on fire (burning point at 650°C). So, except for that hole on the staboard side of the bow, most of visible damage was actually caused by fierce fire that burned the entire bridge (and collapsed its flour), and most... well, actually: all of the bow.