The radical Islamist sect Boko Haram has posted a video threatening to bring down Goodluck Jonathan's regime in Nigeria within three months.

Abubakar Shekau, the purported leader of the ultra-conservative Islamist sect, appears in the video, in which he defies the Nigerian president's recent claim that Boko Haram would soon be brought under control.

In the 14-minute video, the group, known in Arabic as the Jama'atu Ahl-Sunnati Lil Da'awati Wal Jihad, threatens to bring down the country's central government within three months - the same time frame that Jonathan used in reference to bringing the group to heel.

"You, Jonathan, cannot stop us. Instead, we will devour you in three months like you are boasting," Shekau said in the video entitled Message to Goodluck Jonathan.

"We are proud soldiers of Allah; we will never give up as we fight the infidels. We will emerge as winners... We will finish you and end your government," Shekau added using both Arabic and Hausa, a language spoken in the north of the country.

The video is viewed by some observers as a further indication that Boko Haram is unwilling to enter into a dialogue with the central government.

Over the past week, northern Nigeria has been rocked by several attacks by suspected members of Boko Haram.

A bomb attack in the town of Kaduna left at least 46 dead over Easter and another near the border with Cameroon killed at least 10 people.

The group wants to impose Sharia law across Nigeria, which is currently split between Muslims in the north and Christians in the south.

Since Boko Haram stepped up its deadly operations in 2009, the group is reported to be responsible for the deaths of at least 1,000 people.

In the video, Shakau also warns that the group will target anyone who kills its members, regardless of their religion, and accused some people of conducting attacks in Boko Haram's name.

"If death is your worldly gain, for us, it is eternal victory to die working for Allah. Our joy is to die in jihad for Allah against infidels like you," he said.

"We are also aware of some Muslims using our name to make money. We will say nothing, but let them continue and they will meet Allah on the last day.

"We are not doing physical human service, but Allah's work and it is clear your aim is killing us. Let me tell you, with Allah we will triumph over you and your men in hundreds. We are not boasting," he threatened.