"Iran will strongly continue its missile program based on its own defense and national security calculations," foreign ministry spokesman Bahram Ghasemi said in comments published on the ministry's website.
Iran's missile program is not linked to the nuclear deal and does not conflict with the UN Security Council resolution endorsing the agreement, he said. "Iran's missile program has aimed at defense and it is not designed to carry a nuclear warhead," he added.
The US, France, Britain and Germany called in March for the Security Council to discuss "appropriate responses" to Iran's ballistic missile activity, which they said was "destabilizing and provocative."
Iran's nuclear chief Ali Akbar Salehi described the international response as "strange," adding that "I think a conspiracy is taking shape."
Iran is, however, still subject to a UN arms embargo and other restrictions, and the UN resolution includes a provision that would automatically reinstate sanctions if Tehran reneges on its promises.