India has ordered a high-level probe after it accidentally fired a missile into Pakistan, saying it was taking the matter “very seriously”.

The incident happened on 9 March, but India acknowledged it two days later, blaming a “technical malfunction” during maintenance.

India’s defence minister Rajnath Singh told Parliament on Tuesday that the incident was “regrettable”, expressing relief that no-one was killed.

Both countries have nuclear weapons.

Pakistan’s military had said that the “high-speed flying object” had crashed near the eastern city of Mian Channu and its flight path had endangered passenger flights.

It had criticised India’s “callousness and ineptitude” in a “nuclear environment”, and had demanded a joint investigation to “accurately establish the facts surrounding the incident”.

On Tuesday, Mr Singh briefed India’s parliament and said the missile was accidentally released during routine maintenance and inspection of a missile unit.

“It was later known that the missile fell in Pakistan’s territory… I’d like to inform the House that the government has taken this matter very seriously and official order for high-level probe has been given,” he added. “The exact cause of the incident can be known only through a probe.”

Pakistan’s air force said the missile travelled at Mach 3 – three times the speed of sound – at an altitude of 12,000m (40,000ft) and flew 124km (77 miles) in Pakistani airspace before crashing.

“The flight path of this object endangered many national and international passenger flights both in Indian and Pakistani airspace, as well as human life and property of ground,” said Pakistani military spokesman Major-General Babar Iftikhar on 11 March.

A day later, Pakistan’s foreign ministry said it had summoned India’s chargé d’affaires to complain about the incident. Pakistan has also urged India to share the findings of its investigation into what happened.