Opposition parties and civil society groups in Chad said fresh protests would be held on Saturday against the military council that took power after longtime ruler Idriss Deby Itno died fighting rebels.
The Transitional Military Council (CMT) took charge on April 20, the day that Deby's shock death was announced. It is headed by Deby's son Mahamat, a four-star general.
Protests broke out almost immediately and have been brutally quashed, resulting in six deaths according to officials, and nine according to NGOs.
Over 600 people have been arrested.
'We are launching an urgent appeal to all civil society orgnaisations which have not engaged in the fight to immediately join the mass mobilisation,' Max Loalngar, the coordinator of the Wakit Tamma collective told a news conference on Thursday.
The elder Deby systematically banned protests during his 30-year rule.
Mahamat Idriss Deby has pledged to hold 'free and democratic' elections in 18 months. He has named a transitional government that is overwhelmingly dominated by ruling party figures and stalwarts of the old regime.
Chad claims that the Front for Change and Concord in Chad (FACT), a large armed group with a rear base in Libya which mounted an offensive on April 11, is retreating after a government offensive.