A US naval blockade targeting Iranian oil shipments has cost Tehran an estimated $4.8 billion in lost revenue, according to a Pentagon official cited by The Hill on Friday, based on a Defense Department assessment, The Caspian Post reports.

The blockade, imposed on April 13 in and around the Strait of Hormuz, is part of a pressure campaign ordered by President Donald Trump amid stalled negotiations with Iran.

“The United States’ blockade in the Strait of Hormuz is operating with full force and delivering the decisive impact we intended. We are inflicting a devastating blow to the Iranian regime’s ability to fund terrorism and regional destabilization,” acting Pentagon press secretary Joel Valdez said in a statement.

He added that US armed forces in the region will continue to maintain “unrelenting pressure.”

US Central Command (CENTCOM) said American forces have turned away 45 commercial vessels since the operation began. Iran has also reportedly restricted passage in the strait, while US forces have intercepted maritime traffic in the Gulf of Oman.

Separately, President Trump notified Congress that a ceasefire with Iran extends the timeline under the War Powers Act following the conflict’s start on February 28. He was also briefed on Thursday by CENTCOM commander Adm. Brad Cooper and Joint Chiefs Chairman Gen. Dan Caine regarding military options.

“There are options. Do we want to go and just blast the hell out of them and finish them forever or do we want to try and make a deal?” Trump told reporters on Friday, adding that he prefers a negotiated outcome.