DEAD SEA, Jordan — Yemen’s Houthi rebels said on Sunday that they had fired a cruise missile at a $20 billion nuclear power plant under construction in Abu Dhabi, but the United Arab Emirates’ state-run news agency immediately denied the claim.

A statement on the Houthi website said the missile took aim at the “strategic” Barakah nuclear reactor on Saturday, “successfully hitting its target.” The launch was in retaliation for the closing of sea and airports, it said, without offering evidence or providing further details.

The statement quoted a Houthi leader who warned against continuing the blockade, “affirming Yemenis’ right to take sensitive steps.”

On Twitter, the state agency WAM denied the Houthi rebels had launched a missile toward the United Arab Emirates. In another post on Twitter, WAM said, “U.A.E. possesses an air defense system capable of dealing with any threat of any kind and the project of Barakah reactor is immune.”