With this sanction, Shekau and Ansaru will be banned from international travel while their assets would be frozen under the UN al Qaeda sanctions list.
Russia had placed a “technical hold” on the designations two weeks ago because it needed more time to review the listings, but diplomats said they lifted the hold on Wednesday, allowing the sanctions to come into force.
Last month, the Security Council al Qaeda Sanctions Committee blacklisted Boko Haram at the request of Nigeria, following global outrage when the group kidnapped more than 250 girls from the Government Secondary School, Chibok, Borno State, on April 14.
The Islamist militant group was described in the UN listing as an affiliate of al Qaeda and the Organisation of al Qaeda in the Islamic Maghreb. It is subjected to a travel ban, an asset freeze and an arms embargo.
Boko Haram faction Ansaru, blamed for the killing of several Western hostages, is AQIM’s bona fide affiliate in Nigeria, and called itself “al Qaeda in the Land Beyond the Sahara” in a video with a British and Italian hostage in 2011.
Ansaru broke off from the Boko Haram sect in protest after it killed 186 mostly Muslim civilians in Kano in 2012.
Shekau is the purported leader of Boko Haram. A year ago, US Secretary of State, John Kerry, authorised a reward of up to $7m for information leading to his location.
Boko Haram’s five-year-old insurgency is aimed at reviving a medieval Islamic caliphate in modern Nigeria, whose 170 million people are split about evenly between Christians and Muslims. The group is becoming, by far, the biggest security threat to Africa’s top oil producer.