Uthman Abubakar had been treated "courteously" during his detention, but his mobile phones and laptop were still with the military, Daily Trust editor-in-chief Mannir Dan-Ali said in a statement.

"They told him that they needed time to finish the forensic checks they are carrying out on the equipment,” Dan-Ali added.

Abubakar is the newspaper's regional editor in the north-eastern city of Maiduguri, the epicentre of the Boko Haram insurgency. Daily TrustCopyright: Daily Trust

The military defended the raids on the Daily Trust's offices in Maiduguri and the capital, Abuja, saying the newspaper had "undermined national security".

The newspaper condemned the raids as "unlawful".

The Daily Trust reported on Sunday that the military was planning an offensive to retake control of the fishing town of Baga and other towns captured by a Boko Haram offshoot, the Islamic State's West Africa Province (Iswap).

Dan-Ali said the military had also not returned the computers and laptops seized from the newspaper's Abuja office.