KINSHASA - A former DR Congo rebel leader wanted for war crimes by the International Criminal Court on Tuesday denied any involvement in the deadly fighting which has plagued the country's east.

"I am not involved in the clashes pitting the FARDC (regular army) against the soldiers who defected," Jean-Bosco Ntaganda told AFP, in reference to army deserters who previously fought in his rebel group.

Ntaganda's CNDP was incorporated into the army in 2009 following a peace deal with Kinshasa.

But a group of several hundred CNDP loyalists, including roughly a dozen senior officers, defected from the army earlier this month, citing unpaid salaries and inhumane living conditions among other complaints, and regrouped as a rebel force.

Some of the defectors attacked army troops on Sunday at Mwesa in the volatile Kivu Nord province, which borders Rwanda, and clashes have continued in the surrounding areas.

The army said Monday that it had launched an offensive to reclaim territory lost to the rebels and the United Nations reported more than 2,000 civilians had been displaced by the fighting.

The UN's refugee agency (UNHCR) said families have fled to a transit centre in Rwanda, while others had sought shelter in classrooms in the town of Saki, and AFP reporter witnessed late Monday.