GOMA -  A young girl was killed and 31 Indian peacekeepers were injured Tuesday in a grenade explosion in Goma in eastern Democratic Republic of Congo, the UN said.

"A grenade exploded regretably killing a girl of roughly eight-years-old... another civilian was injured," said Bilamekaso Tchagbele, the information chief for the UN's force in the country.

The blue helmets were struck as they were exercising and the injured servicemen were taken to a UN military hospital, he added. "An investigation has been opened to determine where the grenade came from," said Tchagbele.

Abdoul Bikulo, an official in the Kyshero district of Goma where the blast ocurred, confirmed the schoolgirl's death.

The UN Mission in DR Congo (MONUSCO) has more than 20,000 troops in the country protecting civilians and disarming dozens of rebel and splinter groups after two decades of conflict in the east of the country. The mission's troops and police personnel are drawn from over 50 countries including regional nations and was deployed in 1999.

The blast in the east threatens to compound existing tensions in DR Congo, where fears are mounting that President Joseph Kabila plans to hold on to power after his second mandate expires in December. A wave of deadly clashes pitting police against demonstrators hit the country in late September, as the opposition demanded Kabila's resignation. Attacks with explosive devices are extremely rare in Congo and it was not immediately clear who might have been responsible. Paluku said Congolese and United Nations investigators were trying to determine the exact nature of the device.

About 18,000 uniformed UN personnel operate in Congo, where millions of people died in regional conflicts between 1996-2003 and dozens of armed groups continue to operate.