The United States charges Iran's satellite programme is a cover for its development of missiles. The Islamic republic has previously insisted its aerospace activities comply with its international obligations.

Tensions between the arch foes escalated last week with the US accusing Iran of harassing its ships in the Gulf.

The Islamic Revolutionary Guard Corps said the surprise satellite launch was a milestone for the country.

"The first satellite of the Islamic Republic of Iran has been successfully launched into orbit," said the Guards' Sepahnews website.

The satellite dubbed the Nour -- meaning "light" in Persian -- had been launched from the Markazi desert, a vast expanse in Iran's central plateau.

The satellite "orbited the Earth at 425 kilometres (264 miles)" above sea level, said Sepahnews.

The launch was "a great success and a new development in the field of space for Islamic Iran," it added.

State television aired footage from multiple angles of a rocket blasting off into a mostly clear blue sky.

The rocket bore the name Qassed, meaning "messenger", in what appears to be the first time Iran has used a launcher of this type.

- 'Great national achievement' -

Its fuselage also had a Koranic inscription that read: "Glory be to God who made this available to us, otherwise we could not have done it."

There was no way to independently verify the details and timing of the launch.

It was hailed by Iran's Telecommunications Minister Mohammad Javad Azari Jahromi.

"Sincere congratulations to the IRGC Air Force for this great national achievement," he tweeted, adding he had visited the launch site three weeks ago.

"They were great," he said of the satellite and what he described as a "three-stage solid fuel" launcher.

Iran has repeatedly tried and failed to launch satellites in the past.

The most recent was on February 9 when it said it launched but was unable to put into orbit the Zafar, whose name means "victory" in Persian.

Arch enemies Iran and the United States have appeared to be on the brink of an all-out confrontation twice in the past year.

Their long-standing acrimony was exacerbated in 2018 when US President Donald Trump unilaterally withdrew from a deal that froze Iran's nuclear programme, before issuing demands that it curtail its development of ballistic missiles.

- High-seas encounter -

Tensions escalated again in January when the US killed Major General Qasem Soleimani, head of the Guards' foreign operations arm, the Quds Force, in a drone strike in Iraq.

The US Department of Defence last week accused Iran of "dangerous and provocative" actions in the Gulf.

It said 11 Guards boats "repeatedly crossed the bows and sterns" of US vessels in international waters.

Iran said the US gave a "Hollywood" account of the encounter and warned it that any "miscalculation will receive a decisive response".

Washington has also raised concerns in the past about Tehran's satellite programme, saying the launch of a carrier rocket in January 2019 amounted to a violation of limits on its ballistic missiles.

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.

The Islamic republic, battling one of the world's deadliest novel coronavirus outbreaks at the same time as dealing with crippling US sanctions, has accused Washington of "economic terrorism".

Tehran says the punitive measures have denied it access to the medicines and medical equipment it needs to fight the virus.

Iran says the disease has claimed the lives of nearly 5,400 people and infected almost 86,000 since the outbreak emerged on February 19.

The number of Iranians killed and sickened by the virus is widely thought to be much higher, however.

Iran has requested a $5 billion emergency loan from the International Monetary Fund to help it tackle the outbreak.

But the US, which effectively holds a veto at the IMF, has signalled it has no intention of agreeing to such a line of credit.