An explosion at a newspaper office in the Nigerian capital Abuja on Thursday that killed at least three people was a suicide attack, the chairman of the daily ThisDay's editorial board said.

"The suicide bomber came in a jeep," 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."

The two guards were killed in the blast along with the bomber, he said. Five support staff were wounded.

"Fortunately the newsroom is a bit far from the back of the building," said Adeniyi. "So all the people in the newsroom ... are all safe."

The privately owned newspaper is one of Nigeria's most prominent and influential. It is based in the economic capital Lagos, but has a major operation in the capital Abuja.

Another bomb attack at roughly the same time in the northern city of Kaduna targeting a complex that also includes a ThisDay office left at least three people dead as well, making a total of six.