Iran will pursue its development of ballistic missiles despite the US blacklisting of more Iranian companies linked to the program, a senior Iranian commander says.

Key points: US says Iran's missile tests violate UN resolutions

US says Iran's missile tests violate UN resolutions Iran pledges to continue developing its program citing a right to self-defence

Iran pledges to continue developing its program citing a right to self-defence Iran says fear of US sanctions is its biggest threat

The Islamic Revolutionary Guards Corps (IRGC) test-fired several ballistic missiles this month, drawing condemnation from Western leaders who believe the tests violate a United Nations resolution.

The US Treasury Department blacklisted on Thursday two Iranian companies, cutting them off from international finance over their connection to the missile program.

Washington had imposed similar sanctions on 11 businesses and individuals in January over a missile test carried out by the IRGC in October 2015.

"Even if they build a wall around Iran, our missile program will not stop," said Brigadier General Amir Ali Hajizadeh, commander of the IRGC's aerospace arm.

"They are trying to frighten our officials with sanctions and invasion ... this fear is our biggest threat."

US officials said Iran's missile test would violate UN Security Council Resolution 2231, which calls on Iran not to conduct "any activity" related to ballistic missiles capable of delivering nuclear weapons.

However, Washington said that a fresh missile test would not violate a July 2015 accord under which Iran has restricted its disputed nuclear program and won relief from UN and Western financial sanctions in return.

That agreement between Iran and six world powers was endorsed in Resolution 2231.

The Revolutionary Guards, Iran's elite fighting and security force, maintains dozens of short and medium-range ballistic missiles, the largest stock in the Middle East.

It says the missiles are solely for defensive use with conventional, non-nuclear warheads.

President Hassan Rouhani, a pragmatic conservative, said on Sunday that boosting Iran's defence capabilities is a "strategic policy", though Iran should take care not to provoke its enemies.

"We will pursue any measure to boost our defence might and this is a strategic policy," Mr Rouhani was quoted as saying in the first cabinet meeting in the new Persian year.

"But at the same time we should remain vigilant so that Iran's enemies do not find any excuse to take advantage of the situation."

Iran has denied US accusations that it is acting "provocatively" with the missile tests, citing a long history of US interventions in the Middle East — including a US-engineered coup in Tehran in 1953 — and a right to self-defence.

Reuters