Iran said it put its first military satellite into orbit Wednesday, making it an emerging "world power", as the US issued new threats amid rising naval tensions in the Gulf.

The Islamic Revolutionary Guard Corps hailed the launch as a milestone despite repeated US allegations that the space programme is a cover to develop ballistic missiles.

"Today, we are looking at the Earth from the sky, and it is the beginning of the formation of a world power," the Guards' commander Hossein Salami said, quoted by Fars news agency.

Tensions between the United States and Iran escalated again last week with Washington accusing its arch-foe of harassing its ships in the Gulf.

US President Donald Trump took to Twitter on Wednesday to say he had "instructed the United States Navy to shoot down and destroy any and all Iranian gunboats if they harass our ships at sea".

Secretary of State Mike Pompeo charged that the satellite launch proved US charges that Iran's space programme was for military rather than commercial purposes.

"I think Iran needs to be held accountable for what they've done," Pompeo told reporters in Washington.

Iran maintains it has no intention of acquiring nuclear weapons, and says its aerospace activities are peaceful and comply with a UN Security Council resolution.