A suicide attack at the Abuja bureau of a top Nigerian newspaper and a car bombing at another of its offices killed eight people today in the first such strikes against the country's media.
The attack in the capital Abuja saw a suicide bomber drive into the back of the building belonging to This Day, after security guards allowed him through the gate.
Four people were killed, including the bomber and the two security guards, while seven support staff were injured at the privately-owned paper, officials said.
In Kaduna, one of the main cities in the north, a bomb went off outside a complex housing a number of newspaper offices, including for This Day. The attacker then drove his car onto the premises, which later exploded.
Four people were killed and 19 people were injured.
Police said a suspect in Kaduna was arrested and he was suspected to be a member of Islamist group Boko Haram.
A purported spokesman for the Islamist group had recently made threats against news media outlets, saying they were being used by authorities to publish stories against Boko Haram.
The loud blast in Abuja shook the area, sending smoke billowing into the air and causing panic, with memories of a suicide bombing of UN headquarters in the Nigerian capital in August still fresh.
"The suicide bomber came in a jeep," the chairman of This Day's editorial board, Olusegun Adeniyi, told reporters at the scene.
"[Security guards] opened the gate for them ... The guy drove in through the gate and rammed into the building and exploded."
He said that "fortunately the newsroom is a bit far from the back of the building, so all the people in the newsroom ... are all safe."
Damage could be seen to the printing press and other areas, while dozens of security and rescue workers were at the scene, as well as firefighters.
The newspaper is based in the economic capital Lagos, but has a major operation in the capital Abuja.
In Kaduna, witnesses reported a chaotic scene where the attacker left a bomb outside a complex housing newspaper offices, then drove his car onto the premises before leaving the scene.
The bomb outside the premises exploded, while the car later detonated. A local emergency agency spokesman reported at least three dead.
An AFP correspondent reported that police fired shots at the car after it had been left and it exploded twice. Authorities were later said to have discovered three gas cylinders and other explosive devices inside the car.
Boko Haram's insurgency, mainly in northern Nigeria, has killed more than 1,000 people since mid-2009.
It claimed responsibility for an August suicide bombing of UN headquarters in Abuja that killed at least 25 people.
The group's deadliest attack yet occurred on 20 January in the northern city of Kano, the country's second-largest, when co-ordinated bombings and shootings killed at least 185 people.
Nigeria, Africa's most populous nation and largest oil producer, is roughly divided between a mainly Muslim north and predominately Christian south.
An attempt to hold indirect talks between Boko Haram and the government in March collapsed, with a mediator quitting over leaks to the media and a purported spokesman for the Islamists saying they could not trust the government.
President Goodluck Jonathan, currently attending a regional summit in Ivory Coast, condemned the attacks, as did the US, saying that they targeted "free speech itself".