Three people have been wounded after an explosion at a Russian secret service training centre in St Petersburg.

Colonel Rifat Zakirov, a sapper, was hurt trying to defuse an explosive device found under a staircase at the GRU Mozhaisky Military Space Academy on Tuesday.

Colonel Nikolay Kurday was also taken to hospital while local media reported a female teacher at the academy was wounded by shrapnel.

All three had non-life-threatening injuries, according to Russia's Defense Ministry.

Colonel Nikolay Kurday (left) and Colonel Rifat Zakirov (right) were taken to hospital with non-life-threatening injuries after an explosion at a secret service training facility in St Petersberg

A female teacher at the Mozhaisky Military Space Academy was also reported to have been injured by shrapnel after the unidentified device blew up on Tuesday afternoon

Soldiers were evacuated after the bomb, initially reported to be a mine but later described as 'selfmade', was found underneath a staircase

A fire truck is seen outside the Mozhaysky Military Space Academy, which was targeted by a bomber on Tuesday afternoon

The incident unfolded in the early afternoon after an 'unidentified' object was found on the second floor of the building.

Some reports suggested the device was a TM-57 anti-tank mine, but later reports suggested it was 'self-made'.

Military chiefs ordered an evacuation of the building and called in the Academy's own mine-clearing unit to deal with the device.

Colonel Zakirov was hurt as the sappers attempted to cover the device with body armour before it could be disposed of, accidentally detonating it.

Emergency services rushed to the scene of the blast, while several windows were blown out on the second floor.

Ten students were reportedly trapped after the blast destroyed the staircase.

Local news website Fontanka reported that the blast was caused by an improvised explosive device with an equivalent of 200 grams of TNT.

Windows on the upper floor of the building were blown out by the force of the bomb, which is also believed to have destroyed a staircase

Fire crews were among emergency services which rushed to the scene of the blast, located in the Petrogradsky District of St Petersberg

Authorities have not revealed who might be responsible for the killing or whether the suspect it was a terrorist attack

An ambulance leaves the scene of the bomb blast watched by evacuated soldiers