The United States began a naval blockade of the Gulf of Oman and the Arabian Sea on Monday, targeting every ship heading to or from Iran, according to U.S. Central Command. Warships will patrol the waters, monitor traffic and may intercept vessels bound for Iranian ports, irrespective of the vessels' flag states. Ships traveling solely between non‑Iranian ports may still use the Strait of Hormuz, but any craft linked to Iranian trade could be inspected, turned away or seized.

President Donald Trump announced the operation on Monday, saying the move is intended to push Tehran back to the negotiating table after talks collapsed over the weekend. The blockade seeks to choke off Iran's oil shipments, which the Iranian government estimates bring in about $200 million a day. Tehran also levies transit fees of up to $2 million on vessels passing the strait, granting passage to friendly nations while denying it to the United States, Israel and their allies. The resulting congestion has already driven up oil prices in the United States and elsewhere.

Retired Royal Canadian Navy vice‑admiral Mark Norman described the action as a "somewhat desperate act," noting the irony of the United States now blocking a waterway it has long advocated opening. He added, "This is really the only significant remaining pressure point, or point of leverage, the United States has," and emphasized that "this is all about money at the end of the day."

Professor David Carment of Carleton University said the United States and Israel appear unaware of Iran's willingness to retaliate and that the strategy "lacks any long‑term plan" and seems "incredibly ad hoc." He suggested the blockade may be aimed more at curbing China's oil imports than at Iran itself.

Two Iranian‑linked tankers, one carrying oil products and the other diesel, left the strait just before the blockade took effect, according to ship‑tracking data. U.S. warships have been observed near the Persian Gulf and farther out at sea. Norman explained that the U.S. will need to set up patrol zones beyond the gulf, employing surface ships, helicopters and long‑range aircraft to intercept vessels that attempt to enter the strait.

Trump posted on Truth Social that any Iranian ship approaching the blockade would be "immediately eliminated." In response, Iran's military and the Revolutionary Guard warned that "NO PORT in