The US military said it would begin enforcing a blockade of all maritime traffic entering and exiting Iranian ports on Monday. It added that ships coming or going from elsewhere would be allowed to pass through the Strait of Hormuz, a critical waterway through which Iran effectively closed in response to US-Israeli strikes. This comes after negotiators from both sides failed to reach a deal to end the war, which began on 28 February. US President Donald Trump said direct talks with Iran in Pakistan failed because Iran was 'unwilling to give up its nuclear ambitions.' Iran's foreign ministry spokesman blamed the US's 'excessive demands and unlawful requests.'

Trump posted to Truth Social on Sunday, stating that the US is set to blockade any and all ships attempting to enter or leave the Strait of Hormuz. He emphasized that any vessel in international waters that has paid a toll to Iran will not be granted safe passage. 'Any Iranian who fires at us or at peaceful vessels will be BLOWN TO HELL!' Trump added.

The US Navy Commander's handbook defines a blockade as an operation to prevent vessels from entering or exiting enemy-controlled areas. Trump explained that the blockade would begin 'effective immediately' but noted that it would take some time to implement fully.

US Central Command (Centcom) indicated that the blockade would be enforced against vessels of all nations. However, they noted that the freedom of non-Iranian vessels would not be impeded. A blockade could potentially violate maritime law and some analysts question whether this aggressive move will effectively prompt Iran to reopen the strait.

The geography of the strait has historically allowed Iran to leverage its position to negotiate tolls for passage, affecting oil prices significantly. The blockade aims to cut off a crucial revenue stream for Iran and is seen as a strategy to pressure them into accepting US terms for negotiations. Opposition voices in the US Congress have questioned the effectiveness and legal implications of this blockade, highlighting the complex dynamics of international maritime law and diplomatic relations.