Washington DC - President Donald Trump on Friday branded NATO allies "cowards" for not bowing to his demand for military assistance in his unprovoked war on Iran.

Trump has recently swung wildly from saying that the US needs no help to secure the vital Strait of Hormuz for oil tankers and lashing out at other countries for failing to help.

"Without the USA, NATO IS A PAPER TIGER!" Trump posted on Truth Social.

"They didn't want to join the fight to stop a Nuclear Powered Iran. Now that fight is Militarily WON, with very little danger for them, they complain about the high oil prices they are forced to pay, but don't want to help open the Strait of Hormuz, a simple military maneuver that is the single reason for the high oil prices."

Donald Trump Trump scrambles to distance US from Israeli attack on Iranian gas field with confusing post

"So easy for them to do, with so little risk. COWARDS, and we will REMEMBER!"

The 79-year-old, a long-term critic of the Western military alliance, has launched a series of rants against NATO in recent days.

On Thursday, six major international powers, including Britain, France, Germany and Japan said they were ready to "contribute to appropriate efforts" to secure the Strait of Hormuz, which Iran has virtually closed off since the US and Israel launched an unprovoked war at the end of February.

But they have not formally committed to any mission to work in the crucial waterway. Other allies such as Germany and Italy have ruled out doing anything before a truce in the hostilities.

None of the countries Trump has called on to help was consulted before the US-Israeli assault started in the middle of negotiations with Iran over its nuclear program.