AFP reporters heard gunfire erupt near the site in N'Djamena, with tanks seen on the street, while security sources reported that armed men had tried to storm the complex.

The government later said 19 people were killed in the fighting, of which 18 were members of the 24-strong group that launched the assault.

"There were 18 dead and six injured" among the attackers "and we suffered one death and three injured, one of them seriously", government spokesman and Foreign Minister Abderaman Koulamallah told AFP.

Hours after the shooting, Koulamallah had appeared in a video on Facebook, surrounded by soldiers, saying that "the situation is completely under control... the destabilisation attempt was put down."

Chad is a landlocked country in Africa's northern half under military rule that is regularly attacked by the jihadist Boko Haram group in the Lake Chad region.

It has recently ended a military accord with former colonial power France and has faced accusations that it was interfering in the conflict ravaging neighbouring Sudan.

Several security sources said that an armed commando opened fire inside the presidency on Wednesday evening around 7:45 pm (1845 GMT), before being overpowered by the presidential guard.

All roads leading to the presidency were blocked and tanks could be seen on the streets, according to an AFP reporter at the scene.

As civilians rushed out of the city centre in cars and motorcycles, armed police were seen at several points in the district.

The gunfire erupted less than two weeks after Chad held a contested general election that the government hailed as a key step towards ending military rule, but that was marked by low turnout and opposition allegations of fraud.

Several hours earlier on Wednesday, China's Foreign Minister Wang Yi met with President Mahamat Idriss Deby Itno and other senior officials.

- France's last Sahel bases -

The former French colony hosted France's last military bases in the region known as the Sahel, but at the end of November it ended the defence and security agreements with Paris, calling them "obsolete".

Around a thousand French military personnel were stationed there and are in the process of being withdrawn.

France was previously driven out of three Sahelian countries governed by juntas hostile to Paris -- Mali, Burkina Faso and Niger.

Senegal and Ivory Coast have also asked France to leave military bases on their territory.

Deby took power in 2021 after the death of his father, who had ruled the country with an iron fist for three decades.

The country's opposition has branded his government autocratic and repressive.

The desert country is an oil producer, but is ranked fourth from bottom in the United Nations Human Development Index (HDI).

To consolidate his grip on power, Deby has reshuffled the army, historically dominated by the Zaghawas and Gorane, his mother's ethnic group.

On the diplomatic front, he has sought new strategic partnerships, including with Russia and Hungary.