Nigerian Islamist group Boko Haram has claimed responsibility for a weekend suicide attack on a church in the country's northeast which killed 15 people and wounded 40 others.

In an emailed statement to journalists, Boko Haram also threatened renewed attacks on journalists and media houses.

"Today God gave us victory by launching a suicide attack on a church in Yelwa neighbourhood in Bauchi city," the group said in the statement written in the Hausa language widely spoken in Nigeria's north.

While the statement could not be confirmed as authentic, it came from the same email address previously used for similar claims.

The statement did not give a specific reason for the Sunday church attack or disclose the identity of the suicide bomber. 

The group's insurgency has killed more than 1,000 people since mid-2009.

"We are keeping tabs on all comments being made about us... Let no one make any entreaty to us when we perfect our plan and start our operation, especially against journalists," the statement said.

The statement accused journalists of "unbalanced reporting" by publishing statements issued by the Nigerian authorities while ignoring or altering its statements.

A suicide bomber on April 26 blew up his explosives-laden car at the Abuja office of ThisDay newspaper, one of Nigeria's most prominent dailies, killing at least five people.

Another bomber targeted a complex housing newspaper offices, including for ThisDay, in the northern city of Kaduna in a botched attack on the same day.

Boko Haram claimed responsibility for the attacks and threatened to target other media houses, including the Hausa-language services of Radio France and Voice of America.