Iran said its ballistic missile programme was not connected to the UN Security Council resolution adopted Monday that endorses its July 14 nuclear accord with world powers.
"The Islamic Republic of Iran is committed to implementing its commitments... so long as" world powers keep their side of the agreement to lift sanctions in exchange for guarantees that Tehran will not develop a nuclear programme, the foreign ministry said in a statement.
It said Iran would in any case never seek a nuclear bomb, "in line with the historic fatwa (religious decree) of supreme guide Ayatollah Ali Khamenei who has banned the use of weapons of mass destruction".
On its ballistic weapons, the ministry said: "Iran's military capacities, especially ballistic missiles, are strictly defensive and, as they have not been conceived to carry nuclear weapons, they are outside the scope and competence of the Security Council resolution".
Under the terms of the nuclear deal, Iran is barred from developing ballistic missile capable of carrying a nuclear warhead.
Iran says it has built ballistic missiles with a range of 2,000 kilometres (1,200 miles), capable of striking its arch-foe Israel.
The foreign ministry, referring to the intrusive inspections permitted under the accord, said: "Since there has never been nuclear activity at any military site, Iran is certain there will not be any request to inspect such sites" from the UN nuclear watchdog, the International Atomic Energy Agency.
In New York, the Security Council unanimously adopted Resolution 2231 endorsing the historic deal on Iran's nuclear programme.
The passing of the resolution marks formal UN approval for the groundbreaking agreement reached between Iran and the so-called P5+1 group.
Provided Iran respects the agreement to the letter, seven UN resolutions passed since 2006 to sanction Iran will be gradually terminated, the text of the resolution says.
The agreement with Tehran was reached last Tuesday in Vienna by the UN council's five permanent members Britain, China, France, Russia and the United States plus Germany.