GOMA - A seven-year-old schoolgirl has been killed and 32 Indian UN peacekeepers wounded in an explosion in Goma in the eastern Democratic Republic of Congo (DRC), the world body said.

The blast occurred just before 6:30 am on Tuesday while the peacekeepers were exercising in the Kyshero district of Goma.

"An explosive device exploded this morning... when the Indian peacekeepers were conducting their morning exercise," the MONUSCO peacekeeping force said in a statement.

"The blast left one child dead and several people wounded, one civilian and 32 peacekeepers, five of whom were admitted to MONUSCO’s hospital with serious injuries."

Witnesses said the child killed was a girl aged around seven who was on her way to school when the explosion occurred.

A source close to MONUSCO who asked not to be named said the attack "deliberately targeted the peacekeepers at a time when they were unarmed".

The source added that the "home-made" device had been hidden in a can and had been detonated remotely.

The peacekeepers were taken to a UN military hospital.

The UN force has more than 20,000 troops in the country -- where it first deployed in 1999 -- protecting civilians and disarming dozens of rebel and splinter groups after two decades of conflict in the east of the country.

Twisted bolts, metal balls

Several hours after Tuesday’s blast, blood could be seen drying on the dirt road.

A group of children showed journalists about 10 twisted bolts as well as small metal balls.

Witnesses said the metal fragments were spread out over an area 10 metres from the explosion and that MONUSCO and police officers collected most of them.

Santas Acenti Foruguta, a watchman at a nearby building site where a Catholic cathedral is under construction, said he fled as soon as he heard the explosion.

When he returned a short time later, he said he saw Indian peacekeepers "putting injured people in sports gear into their vehicles" before going off, leaving behind the young girl.

UN Secretary General Ban Ki-Moon condemned the killing and appealed in a statement issued by his spokesperson for "rapid action to bring the perpetrators of this attack to justice".

MONUSCO head Maman Sambo Sidikou said the peacekeeping force "remains determined to carry through its mission of protecting the civilian population in support of the DRC government’s efforts".

MONUSCO’s mandate has been beefed up over the years. In 2013 its troops worked alongside Congolese army soldiers to dismantle the M23 rebel movement.

DRC’s political crisis deepened last month after a presidential election, which had been due before the year’s end, was postponed until April 2018.

The opposition has accused President Joseph Kabila, who has been in office since 2001, of manipulating the electoral system to stay in power after his second term ends on December 20.

A 2006 constitutional provision limits the presidency to two terms.

The decision to delay the vote was taken in October by the government and fringe opposition groups following a "national dialogue" - boycotted by much of the opposition - to calm tensions. – AFP