"Regarding cruise missiles, today we have gone from a range of 300 to 1,000 kilometres (621 miles) in less than two years," said Iranian President Hassan Rouhani, during a televised ceremony in Tehran.

The revealing of the missiles comes a day after Washington said it will activate a controversial mechanism aimed at reimposing UN sanctions on Iran, the so-called "snapback" procedure.

"Snapback" aims to restore all international sanctions against Iran that were lifted as part of the 2015 accord with Tehran that sought to prevent it from developing nuclear weapons.

One of the new missiles, the "Haj Qasem", a ballistic missile, was named in honour of top Iranian general Qasem Soleimani, killed in January in an American strike in Baghdad.

State television praised the speed of the ballistic missile as "Iran's long arm for hitting the aggressors", and called on people not to forget "Ain al-Assad", the Iraqi military base housing Americans, hit by Iranian missiles in retaliation for Soleimani's assassination.

The other, a cruise missile, was named in honour of Abu Mahdi al-Muhandis, the Iraqi lieutenant of Soleimani, who was killed in the same Baghdad strike.

"I thank the Ministry of Defence for naming one of its most important missiles in honour of General Soleimani," Rouhani said.

Defence Minister Amir Hatami said that "particular attention was paid to increasing the range" of the missiles.

"In the field of solid fuel ballistic missiles, we have today reached a range of 1,400 kilometres (870 miles)," Hatami said, adding that the missiles had demonstrated their "effectiveness" against "American criminals".

Tensions between Washington and Tehran have been rising, especially since President Donald Trump withdrew the US from the 2015 accord and introduced American sanctions on Iran as part of its "maximum pressure" campaign against the Islamic republic.