Eighteen assailants and one presidential guard died during a foiled attack on the presidential complex in the Chadian capital, N’Djamena, on Wednesday night, a government spokesperson has said.

The attackers attempted to storm the presidential palace while President Mahamat Déby Itno was inside, said Abderaman Koulamallah, who also serves as the foreign minister in the military-ruled, central African country.

Heavy gunfire could be heard just before 8pm (7pm GMT) on Wednesday evening in the centre of N’Djamena. A few hours later, Koulamallah appeared in a live Facebook broadcast surrounded by soldiers, saying the situation had been brought under control. “There is no fear,” he said. “The destabilisation attempt was put down.”

Koulamallah said early on Thursday that 24 assailants armed with knives and machetes had driven to the presidency in a few vehicles that seemed to break down at the entrance, before walking out and stabbing the four entrance guards, killing one and injuring two. They then walked into the presidential compound, where other guards shot at them, killing 18 and detaining six, he said.

Like other countries in the region, Chad has been attacked repeatedly for over a decade by insurgent groups linked to Islamic State, al-Qaida and Boko Haram.

However, Koulamallah said Wednesday’s attack was “probably not” a terrorist act and referred to the attackers as drunken “Pieds Nickeles”, a reference to a French comic featuring hapless crooks.