Hundreds of thousands of people rallied in downtown Tehran on Friday in a government-organized demonstration described as the largest of its kind since the United States and Israel attacked Iran in February.

Participants marched in combat uniform carrying flags, with onlookers cheering, and pledged their readiness to take up arms. They were volunteering for limited military training in an effort the government calls "Janfaday-e Iran," or "the ones who sacrifice their lives for Iran." Estimates varied on how many people volunteered. State media had promoted the event for days.

Iran's government has sought to rally the public and stress national unity even as the economy worsens under a U.S. naval blockade of Iranian ports and new U.S. sanctions intended to increase economic pressure on Tehran.

On Friday, Iran's government also claimed another attack on a tanker in the Strait of Hormuz, a key waterway it has sought to control since the start of the war.