State-of-the-art US missiles were likely used in a deadly strike on a residential area of Iran last month, according to an analysis of footage by weapons experts.

The analysts said a projectile visible in footage of the strike on residential buildings in the southern town of Lamerd was likely a Precision Strike Missile (PrSM). The munition is a new long-range weapon operated by the US military.

According to Iranian state media at least 21 people were killed in at least two strikes on the town that day that hit residential buildings and a sports hall about 300 metres apart.

Centcom - which oversees US military operations in the Middle East - declined to comment.

Lamerd is a town in the Fars province of about 30,000 people, according to the 2016 census. Surrounded by rugged mountains, it is around a 14-hour drive from the capital, Tehran.