Tehran has closed the Strait of Hormuz, one of the world’s most critical oil shipping lanes, in retaliation for Israeli airstrikes on southern Lebanon that left dozens dead, including civilians and a Lebanese army officer.

Iran’s Islamic Revolutionary Guard Corps (IRGC) announced the closure, warning vessels against entering the strait. Officials said the move was necessary after what they described as violations of ceasefire commitments under the recently signed U.S.–Iran memorandum of understanding.

The Strait of Hormuz carries nearly 20% of global crude oil and liquefied natural gas, making its closure a major threat to international energy markets.