Boko Haram said it coordinated the attacks on Nigeria's major daily newspaper ThisDay in the capital, Abuja, and an office building it shares with two other newspapers in the city of Kaduna. It threatened to target other journalists in the future.
In Abuja, the suicide bomber rammed his car through the gates of the ThisDay office and drove into the reception area before the explosion, said Nwakpa O. Nwakpa, a spokesman for the Nigerian Red Cross. The blast killed at least three people and wounded others, Nwakpa said.
Soldiers and police officers quickly surrounded the building, which had part of its roof torn away and all its windows blown out by the force of the explosion. The blast focused on the end of the building with the newspaper's printing press, while the newsroom sat far away from the blast. However, the force of the explosion overturned tables and scattered debris through the journalists' workroom.
The attack in Kaduna also included a car loaded with explosives at an office building ThisDay shares with The Moment and The Daily Sun newspapers. However, people at the office quickly surrounded the car, witnesses said. The driver then began shouting that there was a bomb inside the car, witness Jemilu Abdullahi said.
Those there allowed the man to open the trunk of the car and he pulled out and threw an explosive, which detonated, Abdullahi said. At least four people died in that blast, Nwakpa said. Authorities later arrested the bomber, Kaduna state police commissioner Mohammed Jingiri Abubakar said.
"What I can tell you is that for these dangerous elements, everybody is a target," Abubakar said.
Another bomb exploded late Thursday afternoon on the outskirts of Kaduna, causing unknown injuries, police said.
In a statement published Thursday night by the Premium Times website, a spokesman for Boko Haram said it would attack media again over what the group felt was inaccurate media coverage. The sect is blamed for killing more than 440 people this year alone in its growing sectarian fight against Nigeria's weak central government, according to an Associated Press count.
"This is a war between us and the government of Nigeria," the website quoted a sect spokesman as saying. "Unfortunately the media have not been objective and fair in their report of the ongoing war. They chose to take side."
A journalist with long-standing ties to the sect later told the AP that the statement came from the group. The journalist spoke on condition of anonymity over concerns about his safety.
The sect spokesman particularly blamed ThisDay for publishing stories the group found inaccurate. The newspaper is owned by media mogul Nduka Obaigbena, whose flashy events in Nigeria have drawn celebrities from former U.S. President Bill Clinton to rapper Jay-Z. Obaigbena also has strong ties to the country's elite and the ruling People's Democratic Party.
The newspaper has sparked ethnic and religious violence in the past. In 2002, rioting over an article published by ThisDay suggesting the Prophet Muhammad would have married a Miss World pageant contestant killed dozens in Kaduna.
Gbayode Somuyiwa, an official with ThisDay, said the newspaper and others received a general threat purportedly from the group in January. A statement issued by the newspaper promised it would "not be deterred in our pursuit of truth and reason."
President Goodluck Jonathan also condemned the attack as "ignoble, misguided, horrendous and wicked."
The government will "continue to uphold the constitutional right to freedom of express in general and press freedom in particular," a statement from Jonathan's office read. "Criminal elements bent on instilling fear in the minds of Nigerians and foreigners will not succeed."
Diplomats and military officials say Boko Haram has links with two other al-Qaida-aligned terrorist groups in Africa. Members of the sect also reportedly have been spotted in northern Mali which Tuareg rebels and hardline Islamists seized control of over the past month.
Violence, both blamed on the sect and not, continued unstopped this week across Nigeria's predominantly Muslim north. Authorities said gunmen killed two police officers overnight Thursday in Gombe state, while assailants killed three people Tuesday night at a bar in Yobe state. Police also blamed Boko Haram members for shooting to death a retired government worker in Maiduguri. Late Thursday night, gunfire and explosions could be heard in Gombe, the state capital of Gombe state, but authorities did not immediately answer calls for comment.
Attacks against journalists also remain common in Nigeria, a country of more than 160 million where corruption pervades government and business. In January, Boko Haram gunmen shot and killed a journalist with private network Channels Television during an attack on the northern city of Kano that killed at least 185 people.
"It confirms our fears the media is not safe," said Mohammed Garba, president of the Nigeria Union of Journalists. "Journalists are not safe."