Three prominent Islamic extremist groups in Mali have announced they have merged into one and pledged allegiance to al-Qaida's leader, according to an organization that monitors jihadist websites.

Leaders from Ansar Dine, al-Mourabitoun and al-Qaida in the Islamic Maghreb made the declaration in a video distributed Thursday, according to SITE Intelligence Group. The merged group is now called "Jama'at Nusrat al-Islam wal Muslimeen," which translates to "Support of Islam and Muslims," the monitoring group said.

The merger brings the threat of increased insecurity not only in Mali but also in neighboring West African countries which until recently had been relatively free of deadly attacks by extremist groups. The new group also is a threat to the U.N. peacekeeping force in Mali, the deadliest active U.N. mission in the world.

The declaration comes just a week after former Tuareg separatist rebels began joint patrols with Malian forces in northern Mali, a key step forward for a 2015 peace deal. The joint patrols aim to counter the various extremist threats and other sources of insecurity in the region.

The new merger of the three extremists groups was inspired by the unification of factions in Syria, Iyad Ag Ghaly, the former leader of Ansar Dine, said in the video, according to SITE. Ag Ghaly is leading the combined group, the monitoring organization said.

Islamic extremists linked to al-Qaida took over northern Mali in 2012, exploiting a power vacuum after mutinous soldiers overthrew the president. French-backed forces pushed the extremists from strongholds the following year, but attacks have continued and progressed south.

Ansar Dine emerged in 2012 as a religious alternative to the largely secular Tuareg separatists operating in northern Mali. Ansar Dine had allied itself with al-Qaida before the groups took over the region, though no official declaration was made.

Al-Mourabitoun had claimed responsibility along with AQIM, al-Qaida's North Africa branch, for the November 2015 attack at the Radisson Blu hotel in Mali's capital, Bamako. At least 20 people were killed along with two gunmen during a more than seven-hour siege.