TEHRAN, Feb. 10 (Xinhua) -- Iran preserves the "legitimate" right to develop missiles as the deterrent power, a senior advisor to Iran's supreme leader said Saturday.

To this end, Iran will not seek anybody's permission to develop its missile capabilities, said Ali Akbar Velayati, also the former Iranian foreign minister.

Velayati made the remarks on the sidelines of a meeting with foreign diplomats on the occasion of the 40th anniversary of victory of the Islamic revolution.

He stressed that Iran will not negotiate missile capabilities despite the U.S. pressures and will expand them in the quantity it deems necessary.

Last week, Chief of Staff of Iran Armed Forces Major General Hossein Baqeri said that the Iranian armed forces would keep boosting defense capabilities and deterrent power, including missile program.

The Iranian armed forces would never allow any interference in Iran's defense sphere or missile power, Baqeri said.