Several people were killed in a clash near the headquarters of Chad's internal security agency in the capital N'Djamena, according to accounts given by the government and an opposition party that differed over the origin of the incident.

The violence comes amid tensions ahead of a presidential election set for May and June that could return the Central African state to constitutional rule three years after military authorities seized power.

Internet monitor Netblocks said on X that internet connectivity in Chad was disrupted on Wednesday following reports of an attack on the security agency headquarters.

A government statement said the agency was attacked by representatives of the Socialist Party Without Borders opposition party, led by the party's leader Yaya Dillo, resulting in several deaths.

Detailing a separate incident, the government said a member of the party, Ahmed Torabi, had carried out an assassination attempt against the president of the Supreme Court, Samir Adam Annour. Torabi was arrested, it said in the statement.

The general secretary of the Socialist Party Without Borders told Reuters that the deaths near the security agency occurred when soldiers opened fire at a group of party members.

The general secretary said Torabi had been shot dead on Tuesday and his body was deposited at the agency's headquarters.

On Wednesday morning, party members and Torabi's relatives went to look for his body at the agency and soldiers shot at them, which resulted in multiple deaths, the secretary said, adding the toll was unknown.

The secretary said he was unable to reach Yaya Dillo. Reuters also was unable to contact Dillo.

The government said the situation was now under control, adding that perpetrators of the unrest had been arrested or were being sought.

Chad's Supreme Court in December approved the vote on a new constitution that critics say could help cement the power of junta leader Mahamat Idriss Deby.

His military government is one of several juntas currently ruling in West and Central Africa, where there have been eight coups since 2020, sparking concerns of a democratic backslide in the region.