Iran test-launched a medium-range ballistic missile inside its borders, US officials said on Friday, defying Trump administration demands that it curtail the weapon programme and demonstrating its intent to further push back against US sanctions.

The test came amid heightened tensions between Iran and the West, mainly regarding the safety of commercial shipping in the Persian Gulf and the Strait of Hormuz.

Iran has responded to stepped-up US economic sanctions with a variety of military moves, and the Shahab-3 missile test launch could be considered another signal from Tehran that it will not back down.

The US officials who confirmed the missile launch spoke on condition of anonymity to discuss sensitive information. The White House said in a brief statement that it was aware of reports of a projectile launched in Iran, but White House officials declined to comment further.

Tensions have mounted with Iran over a 2015 nuclear accord it reached with world powers. The deal eased sanctions in exchange for Iran curbing its nuclear programme. President Donald Trump withdrew the United States from the accord last year, reinstating sanctions on Iran and adding new ones. Iran has openly exceeded the uranium enrichment levels set in the accord to try to pressure Europe into offsetting the economic pain of US sanctions.

Trump insists that Iran must agree to limits on its ballistic missile programme, but Iran thus far has refused.

Take a look: Iran denies any intention of boosting range of missiles

Nations still party to the nuclear deal plan to meet in Vienna on Sunday to see to what extent the agreement can be saved. The European Union said the meeting of officials from China, Russia, Britain, France and Germany will be chaired by the EU.

Behnam Ben Taleblu, an expert on Iranian defense at the Foundation for Defense of Democracies, said the Shahab-3 is a liquid-fueled, medium-range ballistic missile capable of carrying a nuclear weapon.

“The Shahab-3 is the backbone of Iran's class of medium-range ballistic missiles,” he said, adding that Iranian news outlets have previously called it one of the country's “Israel-hitting” missiles.

It is derived from a North Korean missile called the Nodong-A and can fly 1,150 to 2,000 kilometres, or up to 1,242 miles, depending on the variant.

“Iran's continued flight-testing has both political and military applications, functioning as a show of resolve against foreign adversaries and to improve the overall reliability of its missile force, which is the largest in the Middle East,” he said.

“As Iran continues to escalate in response to the maximum-pressure campaign, Washington should expect more missile launches.”