The Iranian regime claims it has built a third underground ballistic missile production factory and will keep developing its missile program.
The announcement was made by the Fars news agency, affiliated to the Revolutionary Guards (IRGC), which quoted a senior IRGC commander.
The development is likely to fuel tensions with the United States in a week when President Donald Trump, on his first foreign trip, has called Iran's regime a sponsor of militant groups and a threat to countries across the Middle East, Reuters reported.
"Iran's third underground factory has been built by the Guards in recent years ... We will continue to further develop our missile capabilities forcefully," Fars quoted Amirali Hajizadeh, head of the IRGC’s airspace division, as saying.
Since taking office in January, Trump has imposed new sanctions on Iran's regime in response to its recent missile launches, putting Tehran "on notice".
The Iranian regime's President Hassan Rouhani said on Monday: "Iran does not need the permission of the United States to conduct missile tests".
Countries in the region have expressed concerns over Tehran's ballistic missile program, seeing it as a threat to regional security.
In 2015, Iranian state TV aired footage of underground tunnels with ready-to-fire missiles on the back of trucks, saying the facility was one of hundreds of underground missile bases around the country.
"It is natural that our enemies America and the Zionist regime (Israel) are angry with our missile program because they want Iran to be in a weak position," Hajizadeh said.
Most nuclear-related sanctions on Iran's regime were lifted last year as part of the international nuclear agreement with Tehran. But the Iranian regime remains subject to a U.N. arms embargo and other restrictions.
Two months after implementation of the deal, the IRGC test-fired two ballistic missiles that it said were designed to be able to hit Israel.
"Along with improving our defense capabilities, we will continue our missile tests and missile production. The next missile to be produced is a surface-to-surface missile," said Hajizadeh, without elaborating.