West African leaders were holding an extraordinary summit in Niamey, Niger, on Saturday, over the escalating crisis engulfing Guinea Bissau.
President Alpha Conde has been trying to amend the constitution to run for a third term. The Summit is attended by ECOWAS heads of state and government.
On Thursday, demonstrators vowed to march peaceful and demand the release of government critics imprisoned since the beginning of anti-government unrest.
Local and international media reported that tension in the country were high just three days after the death of three youths shot by security forces as they attended a funeral march for 11 people killed in unrest since mid-October, according to the opposition.
At least 16 civilians and a police officer have been killed during weeks of bloody classes between demonstrators and security forces, with many more injured or arrested.
Most ECOWAS leaders plan to attend the summit, although Nigerian Vice President Yemi Osinbajo will be representing President Muhammadu.