The civil society group, Socio-Economic Rights and Accountability Project (SERAP), has condemned the presidency for comparing Omoyele Sowore and Olawale Bakare with Boko Haram militants.
PREMIUM TIMES earlier reported the presidency on Sunday justifying the treatment of Mr Sowore by the State Security Service (SSS).
"Sowore called for a revolution to overthrow the democratically elected government of Nigeria.
"He did so on television, and from a privileged position as the owner of a widely read digital newspaper run from the United States of America," Garba Shehu, President Buhari's spokesperson, wrote in a statement sent to PREMIUM TIMES.
Mr Shehu was evasive on whether or not the president authorised the disobedience of court orders by the SSS in detaining Mr Sowore.
"The DSS does not necessarily need the permission of the Presidency in all cases to carry out its essential responsibilities that are laid down in the Nigerian Constitution - which was the foundation for the restoration of democracy in our country in 1999," the spokesperson said.
He also kept mum on whether or not Mr Buhari ordered Friday's invasion of court premises by SSS operatives in a bid to rearrest Mr Sowore.
Mr Sowore, the publisher of Sahara Reporters online newspaper, and Mr Bakare were arrested and detained by the SSS for over 120 days despite two separate court orders for their release.
Arrested for planning anti-government protests, they were only released last Thursday night after Justice Ijeoma Ojukwu gave the SSS 24 hours to release them.
Both men are being prosecuted for treason and insulting President Buhari.
Mr Sowore was, however, rearrested at the Federal High Court in Abuja on Friday morning in a move condemned by local and international rights groups, officials and governments.
In his statement on Sunday, however, Mr Shehu defended the SSS actions and compared Mr Sowore's call for revolution to the Boko Haram insurgency.
According to a statement on its Twitter page this afternoon, SERAP said it is "unacceptable to compare citizens who are also activists simply exercising their human rights including freedom of expression with militants who are killing our people and destroying property."
SERAP said what is happening to Messrs Sowore and Bakare shows clear attempts by the Nigerian authorities to further silence critics, activists and the media while they continue to undermine the rule of law and the independence of the judiciary.
Below is the full statement:
"We condemn the statement today by @NigeriaGov issued by Garba Shehu, Senior Special Assistant (Media and Publicity) to President Muhammadu Buhari, which seems to Boko Haram militants. To be absolutely clear: Sowore and Bakare are not terrorists."
It's unacceptable to compare citizens who are also activists simply exercising their human rights including freedom of expression with militants who are killing our people and destroying property.
Freedom of expression is not yet a crime under the Nigerian Constitution of 1999 (as amended).
What is happening to Sowore and Bakare shows clear attempts by the Nigerian authorities to further silence critics, activists and the media while they continue to undermine the rule of law and the independence of the judiciary.
This is illustrated through a persistent disobedience of court orders, and as we witnessed last week, the invasion of Justice Ojukwu's court by the DSS.
The persecution of Sowore and Bakare is sending a chilling and unambiguous message to all Nigerians, and is part of a systematic effort to silence independent media and critical voices in Nigeria to prevent public scrutiny of governments at both the Federal and state levels.
Nigerian authorities now need to begin to protect citizens' human rights and the rule of law. That should start with the immediate withdrawal of the bogus charges against Sowore and Bakare and the immediate and unconditional release of Sowore from arbitrary detention.
We are concerned that Nigerian authorities continue to openly scorn the Nigerian Constitution and the country's human rights commitments.
This concerted attack on the rule of law must stop.
The UN, African Union, African commission on human and peoples' rights and members of the international community can make a unique impact by speaking forcefully and publicly in defense of human rights, the rule of law and independence of the judiciary in Nigeria.