The minister claimed US cyber attacks against Iranian targets have not been successful (Representational)

U.S. cyber attacks against Iranian targets have not been successful, Iran's telecoms minister said on Monday, within days of reports that the Pentagon had launched a long-planned cyber attack to disable his country's rocket launch systems.

Tension runs high between longtime foes Iran and the United States after U.S. President Donald Trump on Friday said he called off a military strike to retaliate for the Middle East nation's downing of an unmanned U.S. drone.

On Thursday, however, the Pentagon launched a long-planned cyber attack, Yahoo News said, citing former intelligence officials. The cyber strike disabled Iranian rocket launch systems, the Washington Post said on Saturday.

"They try hard, but have not carried out a successful attack," Mohammad Javad Azari Jahromi, Iran's minister for information and communications technology, said on social network Twitter.

"Media asked if the claimed cyber attacks against Iran are true," he said. "Last year we neutralised 33 million attacks with the (national) firewall."

Azari Jahromi called attacks on Iranian computer networks "cyber-terrorism", referring to Stuxnet, the first publicly known example of a virus used to attack industrial machinery, which targeted Iran's nuclear facilities in November 2007.

Stuxnet, widely believed to have been developed by the United States and Israel, was discovered in 2010 after it was used to attack a uranium enrichment facility in the Iranian city of Natanz.

Washington accused Tehran of stepping up cyber attacks.

Officials have detected a rise in "malicious cyber activity" directed at the United States by people tied to the Iranian government, Chris Krebs, director of the Department of Homeland Security's cybersecurity agency, said on Saturday on Twitter.