The United States has threatened sanctions against ally Oman if it assists Iran in imposing a tolling system in the Strait of Hormuz, Treasury Secretary Scott Bessent said Thursday.

“Oman, in particular, should know that the US Treasury will aggressively target any actors involved — directly or indirectly — in facilitating tolls for the Strait,” Bessent warned in a post on X, adding that Washington “will not tolerate any effort” to impose fees in the vital waterway.

The Strait of Hormuz, through which about 20 percent of global energy supplies pass, has become a flashpoint since the US and Israel launched strikes on Iran in February. Tehran has retaliated with near-blockades, driving up energy and fertilizer prices worldwide.

Oman, which has mediated in the conflict and itself faced Iranian attacks, is under growing pressure. On Wednesday, President Donald Trump appeared to threaten Muscat directly, saying he would “blow them up” if Oman joined Iran in controlling the strait — though the White House did not clarify whether he had misspoken.

Bessent’s warning came hours after Washington sanctioned Iran’s newly created “Persian Gulf Strait Authority,” which collects transit fees. The US extended penalties to anyone paying the tolls, citing links to Iran’s Revolutionary Guards.

The tensions erupted as Washington and Tehran accused each other of violating a fragile truce, following the most serious exchange of fire since their April ceasefire. Indirect talks to end the war remain stalled.