As the war in the Middle East entered its fourth week, Iran has widened its warnings to target buyers of U.S. Treasury bonds, the latest salvo in an intensifying exchange of threats, as the Trump administration’s 48-hour ultimatum neared expiry.

In a social media post on Sunday, Iran’s Parliament speaker Mohammad Bagher Ghalibaf said that U.S.-linked financial institutions holding American government bonds would be targeted alongside military bases.

“U.S. treasury bonds are soaked in Iranians’ blood. Purchase them, and you purchase a strike on your HQ and assets,” Ghalibaf said. “Alongside military bases, those financial entities that finance the U.S. military budget are legitimate targets,” he added in the post.

The escalating warning came after U.S. President Donald Trump issued a 48-hour ultimatum to Tehran on Saturday to reopen the Strait of Hormuz — a key artery for global energy shipping — or face strikes on its power plants. The deadline is set to expire on Monday evening in Washington.

Israeli Prime Minister Benjamin Netanyahu vowed to back the U.S. threat: “Whatever we do, we do together, and as far as possible, in confidence.”