The UN mission in the central African country said the explosion occurred Tuesday morning as the Indian peacekeepers were exercising on the outskirts of Goma, the provincial capital on the Rwandan border.
Officials said one of the dead was a peacekeeper and the other was an 8-year-old child. The injured were taken to a UN military hospital.
Officials were investigating whether the grenade belonged to the peacekeepers or whether it had come from some other source.
The UN Mission in the DR Congo, known as MONUSCO, has over 20,000 troops to disarm scores of rebel and splinter groups that have been wreaking havoc in the impoverished country for the past two decades.
The most infamous of the rebel groups is the Allied Democratic Forces (ADF), which was founded in Uganda in 1995 and later moved to the DR Congo, spreading its reign of violence, particularly in the North Kivu province.
In its almost two decades of presence there, the rebel group has been accused of committing serious human rights violations, including recruiting child soldiers and rape, against the local population.
The MONUSCO, comprised of forces from over 50 countries and deployed in 1999, says it aims to protect civilians from violence.
The Congolese army, joined by UN troops, is currently on the offensive against the ADF and other rebel groups.
Congo has been in political turmoil since President Joseph Kabila announced plans to prolong his tenure by postponing the general elections from December 2016 to April 2018.
He is barred by constitution from standing for a third term but the opposition is accusing Kabila of manipulating the electoral system to stay in power.
Kabila has ruled the mineral-rich country since 2001, when his father was assassinated. Under the constitution, he should relinquish power on December 20, but he allegedly seeks ways, including pushing back the elections, to extend his presidency.
In September, a wave of deadly clashes pitting the police against demonstrators rocked Kinshasa as the opposition demanded Kabila's resignation. Over 50 civilians were killed in the clashes and dozens more were injured.
For the past few decades, the DR Congo has also been facing grinding poverty, crumbling infrastructure and regional conflicts in the east of the country that has dragged on since 1998 and left over 5.5 million people dead, Press TV reported.
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