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 is running high between longtime foes Iran and the United States after Iran shot down a U.S. drone on June 20. U.S. President Donald Trump ordered a military strike to retaliate but on Friday he said he called off the strike.

On Thursday, however, the Pentagon launched a long-planned cyber attack, Yahoo News said, citing former intelligence officials. The cyber strike disabled Iranian missile 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.

An Iranian navy commander on Monday described the shooting down of the U.S. drone as a "firm response" to the United States and warned it could be repeated.

"Everyone saw the downing of the unmanned drone," navy commander Rear Admiral Hossein Khanzadi was quoted as saying by the Tasnim news agency.

"I can assure you that this firm response can be repeated, and the enemy knows it."

"We welcome defusion of tensions in the region. We do not want rise of tensions," Abbas Mousavi, Iran's foreign ministry spokesman, was quoted as saying by ISNA news agency.

Last year, Trump withdrew the United States from a 2015 accord between Iran and world powers that curbed its nuclear program in exchange for easing sanctions. Relations in the region have worsened significantly since then.

Trump said on Sunday he was not seeking war with Iran and would be prepared to seek a deal to bolster its flagging economy, an apparent move to defuse tensions.

(With input from Reuters)