The Department of State Services (DSS) has released Adejuwon Soyinka, the West African editor of The Conversation Africa.
Soyinka, a former pioneer editor of the BBC pidgin service, was arrested early Sunday morning by the secret police, at the Murtala Muhammed International Airport in Lagos.
The journalist was detained by the operatives on arrival at the airport from the UK.
Peter Afunanya, the DSS spokesperson, had told TheCable that he was not aware of the arrest of the journalist.
TheCable understands that Soyinka was released following the intervention of the International Press Institute (IPI) Nigeria, a global network of editors, media executives, and communication experts.
Security operatives have intensified attacks on journalists since the turn of the year.
In March, Segun Olatunji, a former editor of FirstNews, was arrested in Lagos.
In May, Daniel Ojukwu, a journalist with the Foundation for Investigative Journalism (FIJ), was detained by the police for 10 days.
In May, Jamil Mabai, a freelance journalist, was detained by the Katsina Hisbah religious police.
The Nigeria Police Force National Cybercrime Centre (NPF-NCCC) has also detained several journalists and whistleblowers over petitions filed against them.