The capital of Chad appeared calm on Wednesday morning, with security forces deployed in large numbers and burning tyres still smouldering in the streets, a day after at least five people were killed in clashes between protesters and the army.

Civil society groups have called for more demonstrations against the military, which took power after long-serving president Idriss Deby was killed on April 19.

The government said five people were killed in clashes on Tuesday. A Chadian civil society group put the death toll at nine, with dozens more injured.

Although opposition and civil society groups called for demonstrations to continue on Wednesday, protesters appeared to be staying home in the capital N'Djamena, at least in the morning.

"We want to give a bit of time for the families of our comrades to mourn their loved ones. The fight continues," said Digri Parterre, one of the protest leaders, who said he had spent the morning visiting the wounded in hospitals.

In an apparent sign that Western countries long supportive of Deby want to keep communications open with his opponents, opposition figure Succes Masra tweeted on Wednesday that he had been visited by US Ambassador David Gilmour. The embassy could not immediately be reached for comment.

Deby was killed on April 19 as he visited troops fighting rebels opposed to his 30-year rule. His death came just a week after he was re-elected in a vote the opposition says was rigged. A military council headed by his son took control of the country after his death, a move which opposition politicians have condemned as a coup.

The government issued a statement on Monday saying all protests were banned, and security forces used tear gas to disperse hundreds of demonstrators. Reports on social media said live ammunition was used in certain places on Tuesday. Reuters was not able to verify those reports independently.

French President Emmanuel Macron, who initially backed the military takeover, appeared to shift his position on Tuesday, calling for a civilian-led unity government until elections to be held within 18 months.

France has a military presence in its former colony and was a long-term backer of Deby.

The Libya-based rebel group that claimed responsibility for Deby's death, known as the Front for Change and Concord in Chad (FACT), issued a statement condemning the use of force against protesters and said it would remain engaged in the fight for a democratic transition.

FACT rebels came as close as 200-300 km (125-185 miles) from N'Djamena last week before being pushed back by the army, which has refused to negotiate and called for them to be tracked down and arrested.