Iran’s Defense Minister Amir Hatami said on Thursday that the formation of a US-led flotilla in the Gulf would “increase insecurity” and any Israeli involvement would have “disastrous consequences” for the region.
Tehran and Washington have been locked in a battle of nerves since US President Donald Trump withdrew from a landmark 2015 nuclear deal with Iran last year and re-imposed sanctions.
Tensions have soared in the region, with drones downed and tankers mysteriously attacked in Gulf waters.
Washington and its Gulf allies have accused the Islamic republic of the tanker attacks, which Tehran denies.
In response, the US has been seeking to form a coalition whose mission- dubbed Operation Sentinel - it says is to guarantee freedom of navigation in the Gulf.
Britain, which already has warships on protection duty in the Gulf after a UK-flagged tanker was seized by Iranian Revolutionary Guards, has said it will join the planned operation.
But other European countries have kept out, for fear it might harm European efforts to reach a negotiated settlement with Iran.
Iran has seized three tankers in the Gulf since last month, including the British-flagged vessel.
The ship seizures came after British Royal Marines helped to impound a tanker carrying Iranian oil off the British overseas territory of Gibraltar on July 4, alleging it was destined for EU-sanctioned Syria, an accusation Iran denies.