A Nigerian radical sect has purportedly threatened several domestic and international news organizations, including the Hausa service of Voice of America.

The threats are contained in an 18-minute video posted to YouTube on Tuesday in the name of the Islamist group Boko Haram.

The video shows a car bomb exploding in Abuja last Thursday outside an office of This Day, one of Nigeria's most prominent national newspapers.

Later, scrolling text notes that the group has complained about “bad press,” and an unnamed man, sitting next to a rifle, threatens seven other Nigerian papers and VOA's Hausa service, which broadcasts to Nigeria.

The authenticity of the video could not be immediately confirmed.

In a statement, VOA spokesman David Borgida said, “VOA has no comment but takes the safety of all its journalists very seriously.”

Boko Haram, which calls itself Ahlis Sunnah, previously claimed responsibility for the Abuja blast, which killed three people. It also claimed responsibility for a blast near This Day's office in the city of Kaduna, which killed four.

Human Rights Watch says the group has been responsible for more than 1,000 deaths over the past three years, mostly in the north.

Boko Haram says it is fighting to impose Islamic law in Nigeria and does not recognize the country's constitution.

In the video, the group says it attacked This Day because the newspaper and other media outlets have published lies about the group and defamed Islam.

It accuses Nigeria's government of arresting wives and children of the group's members and demolishing their houses.

Nigerian President Goodluck Jonathan has vowed to crush the group and has increased security across the north.