GOMA, DR Congo - The March 23 Movement (M23) rebel group on Thursday accused the Democratic Republic of the Congo (DRC) military of repeated ceasefire violations ahead of a crucial peace talks deadline, warning that it would strike back if attacked.

The warning came one day before an agreed deadline to begin formal peace negotiations under the Declaration of Principles signed between the DRC government and the M23 on July 19 in Doha, Qatar. However, the M23 said it had not been invited to the latest round of discussions.

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"We are not in Doha because no invitation was extended to us," M23 political leader Bertrand Bisimwa told reporters at a press conference in Goma, capital of North Kivu province, a regional hub seized by the group since late January.

Bisimwa accused the DRC military of repeated violations of the ceasefire. "Starting from today ... every attack will be met with an appropriate response aimed at neutralizing the threat once and for all, in order to protect the civilian population," he said.

The Declaration of Principles outlines a commitment to a permanent ceasefire and prohibits any attempt to seize new positions by force. It also stipulates that negotiations on a peace accord must begin by Aug 8, giving the parties less than two weeks to finalize a deal by the Aug 18 deadline.

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Kinshasa and the M23 have held several rounds of talks in Doha since late March under Qatari mediation. However, tensions have grown in recent weeks as implementation of the Doha framework stalled.

On July 25, Benjamin Mbonimpa, M23's representative in several rounds of talks with Kinshasa in Doha, threatened that the group could withdraw from the timetable outlined in the Declaration of Principles.

"Implementation of that declaration was to come before negotiations," he said. "If nothing happens within the set timeframe and if Kinshasa does not release our prisoners by July 27, we have no reason to return to Doha."

UN High Commissioner for Human Rights Volker Turk on Wednesday condemned the escalation in deadly attacks by the M23 and other armed groups against civilians in the eastern DRC over the past month.

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According to first-hand accounts received by the UN Office of the High Commissioner for Human Rights, between July 9 and 21, at least 319 civilians were killed by the M23 in four villages in the Rutshuru territory, in North Kivu. Most of the victims, including at least 48 women and 19 children, were local farmers camping in their fields during the planting season.

According to the UN, more than 27.8 million people in the DRC are facing food insecurity, with over 7 million internally displaced, many of them multiple times.