The death toll from Thursday's bomb attacks on Nigerian newspaper offices in the capital Abuja and the northern city of Kaduna has risen to at least nine people.
Suspicion has fallen on the militant Islamist sect Boko Haram, which has threatened the media in the past, but Nigerian journalists say they will not be deterred from disseminating information.
The Premium Times, a local online publication, posted what it said was an exclusive interview with the group's spokesman late Thursday. Known as Abul Qaqa, the purported Boko Haram spokesman reportedly said the bombings were payback for dissemination of what he called inaccurate and biased reports on the sect's activities, and that ThisDay, a prominent Nigerian newspaper, was targeted for particularly serious "sins."
Qaqa usually communicates with local reporters via teleconference, and the authenticity of the published interview was not immediately verifiable.
Standing outside the bombed-out newspaper office in Abuja Thursday, ThisDay's executive director Israel Iwegbu defended the paper's reporting.
"We've always quoted their representative, their spokesman," he said. "We've always said whatever that man said. We have never gone out of the way to report anything against them whatsoever. We report things as they are."
On Friday, ThisDay published an editorial saying "no amount of threat or intimidation can weaken our resolve." The paper said Thursday's late morning blast killed five people, including the bomber, after a jeep rigged with explosives rammed the front doors of its Abuja office and printing press.
Later in the day, bombings in the northern city of Kaduna killed at least four other people and injured several more. One of the latter attacks targeted a building that houses local offices for three newspapers: ThisDay, The Sun and The Moment. In that attack, police said they arrested a bomber after witnesses said a mob tried to beat him to death.
The Kaduna bureau chief for The Moment, Garba Mohammed, said all Nigerian news outlets face significant challenges in covering Boko Haram, which remains a largely "faceless" entity. To cover the news, he said, reporters must often go by unverified statements from security forces.
"They are always very, very challenging," said Mohammed. "They don't open up with all of the truth of the matter, and we are always left with the accounts of eyewitnesses to rely on."
Thursday's attacks underscore the growing complexity of the security threat in northern Nigeria, as bombings and drive-by shootings -- not all of which are claimed by Boko Haram -- increasingly target civilians. Beefed-up security has not been able to stop the near-daily violence.
Boko Haram has made threats against media outlets in recent months, but even if claims of responsibility are confirmed, said Igwegbu, journalists would be merely another addition to a growing roster of targets.
"We are calling on the president to sit up and assure the security of lives and property, because if they can target the schools, people in church, media organizations like ThisDay, then apparently there is no one that is safe."
Boko Haram, the Islamist sect's nickname in the Hausa language, means "Western education is sacrilege," a condemnation of what the group calls a wealthy, foreign-educated elite that has confiscated power in Nigeria. The sect has said it wants to impose Islamic law in northern Nigeria.
According to Human Rights Watch, Boko Haram has killed more than 1,000 people since its 2010 resurgence.