After the incident, tanks were seen in the area and all roads leading to the palace were closed, the agency reported.
In a video posted on Facebook, Kulamalla is seen surrounded by members of the government forces.
“Nothing serious happened,” he says.
“We are here and will protect our country at the cost of blood. Be calm.
“This whole attempt at destabilization has been thwarted.”
He is then seen taking pictures with the soldiers and raising his fist with them.
AFP quoted Kulamallah as saying the assault was launched by a 24-man commando unit, adding that six of the attackers were wounded.
Three other members of the government forces were also injured, he added.
The incident came hours after a visit to the former French territory by Chinese Foreign Minister Wang Yi, who met with President Mohamed Deby and other senior officials.