Nigeria’s state security agency on Wednesday denied that its officers opened fire on campaigners calling for the release of the former presidential candidate and activist, Omoyele Sowore who remains in detention despite having been granted bail.

Sowore, who ran for president as a minor candidate in the February election in which former military ruler President Muhammadu Buhari secured a second term in office, was arrested in August for calling for a revolution.

In September Sowore pleaded not guilty to charges of treason, money laundering and harassing the president. He was granted bail on Oct. 4 but he has not been released because the Department for State Security (DSS) says the conditions have not been met.

Supporters of Sowore, who founded Nigerian online news organization Sahara Reporters, staged a protest at DSS headquarters in the capital, Abuja, on Wednesday during which they said the security agency’s officers opened fire on them.

But the claims were denied by the DSS.

“Despite serial and unwarranted provocations, the Service, as a professional and responsible Organisation, did not shoot at the so-called protesters,” the DSS said in a statement.

Sowore’s continued detention has prompted some to criticize Buhari over his administration’s record on human rights, particularly a lethal crackdown on followers of a Shi’ite leader who has been detained by the government since 2015 without a trial.

Nigerian campaign groups, including Concerned Nigerians Group and the Coalition in Defence of Nigerians Democracy and Constitution, issued a statement in which they said “violent attacks” on protesters at DSS headquarters show that Buhari “is running a dictatorship again”.

Buhari was Nigeria’s head of state between December 1983 and August 1985, after taking power in a military coup. He was also replaced by the military.

Sowore was granted bail so long as a number of conditions were met including the provision of 100 million naira ($277,777) with two sureties.

The DSS, in its statement, said it reiterated its “avowed readiness to release Sowore” once the people who provided surety for him had presented themselves.

Femi Falana, a lawyer representing Sowore, on Wednesday called on the DSS to release his client from “illegal custody”.

He accused the DSS of “aggravating the felony of contempt of court by asking sureties who had been verified by the trial court to report in its office for an illegal verification”.