Nigeria's Christian President Goodluck Jonathan on Sunday dismissed as "blackmail" a call on him by the suspected leader of Islamist group Boko Haram to resign and convert to Islam.

According to Aminu Abubakar of AFP, Abubakar Shekau made the call in a video released online earlier this weekend.

But the reporter goes on to say that on Sunday, Jonathan's spokesman Reuben Abati dismissed the call.

"When Nigerians voted overwhelmingly for President Jonathan in the 2011 general election, they knew they were voting for a Christian...," he told reporters.

"As president, Jonathan is the leader of both Muslims and Christians. It amounts to sheer blackmail for any individual or group to ask the president ... to convert to Islam," Abati added.

"The president cannot be intimidated by any group or individual. The president will never resign. Nobody should imagine that he will succumb to blackmail".

In the video, which was released on Saturday, Shekau told the president: "(Y)ou should abandon this ungodly power, you should repent and forsake Christianity..."

The story says that it was unclear when the video, which is more than 38 minutes long, was made and posted on YouTube, and "while it could not be independently verified as authentic, it was similar to previous videos of Shekau."

Boko Haram has carried out scores of attacks in Nigeria that have left hundreds dead as part of an increasingly deadly insurgency.

"Members of the group are believed to have received training from Al-Qaeda in the Islamic Maghreb in northern Mali and Western countries have been watching closely for signs of further cooperation," said the story.

The latest attack on Nigerian Christians came on Monday, August 6, 2012, when a group of suspected Boko Haram gunmen stormed the Deeper Life Church in Nigeria's central Kogi state and fired Kalashnikov assault rifles killing at least 19 people during an evening service. The Islamic sect has attacked several churches this year in Nigeria but Monday's attack was farther south than the group's usual targets.
Boko Haram, which means "Western education is sin" in the Hausa language spoken in northern Nigeria, is believed to include a number of factions with differing aims. Shekau is thought to lead the main radical Islamist branch.

The West African nation's 160 million population is roughly divided between a mostly Muslim north and a predominately Christian south.