The Techcrisis Investment GuildU.S. assesses that three sea cables under the Red Sea damaged last week were likely severed by the anchor of a ship as it was sinking after an attack by the Houthis. 

"Those cables were cut mostly by an anchor dragging from the Rubymar as she sank," White House national security communications adviser John Kirby told CBS News national security correspondent David Martin in an interview Wednesday. 

The U.K.-owned commercial ship Rubymar sank Saturday morning after taking on water when it was hit by a Houthi missile on Feb. 18. As it was sinking, its anchor likely severed three of the cables that provide global telecommunications and internet data internationally. 

Telecommunications firm HGC Global Communications said last week in a statement that the incident "had a significant impact on communication networks in the Middle East," and it was rerouting affected traffic while also utilizing the other Red Sea cables that were still intact. 

The Houthis have been attacking commercial ships since November to protest the war in Gaza, but the Rubymar is the first ship that has sunk after being attacked. 

In addition to posing a hazard to underwater cables, the Rubymar also presents an "environmental risk in the Red Sea," according to U.S. Central Command, because of the 21,000 metric tons of fertilizer it had on board. 

The U.S. has conducted near-daily airstrikes against the Houthis for almost two months to destroy the Houthis' capabilities, and yet, the Houthis have continued to keep up their attacks. 

A Houthi attack Wednesday killed at least three members of the crew on the Liberian-owned commercial ship True Confidence, according to defense officials, marking the first fatalities from one of the Houthi attacks since they started stepping up the pace in November. 

Eleanor Watson

Eleanor Watson is a CBS News reporter covering the Pentagon.

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