The UN Security Council has officially declared Boko Haram a terrorist group linked to al-Qaeda and imposed sanctions against the Islamists who have carried out a wave of deadly attacks and the recent abduction of nearly 300 schoolgirls in Nigeria.
US ambassador Samantha Power welcomed the council's action on Thursday, calling it "an important step in support of the government of Nigeria's efforts to defeat Boko Haram and hold its murderous leadership accountable for atrocities".
Nigeria, which is serving a two-year term on the council, asked the Security Council committee monitoring sanctions against al-Qaeda to add Boko Haram to the list of linked organisations subject to an arms embargo and asset freeze.
There were no objections from the 14 other members.
Australian UN ambassador Gary Quinlan, who chairs the al-Qaeda sanctions committee, said there was "very clear evidence" that Boko Haram members had trained with al-Qaeda in the Islamic Maghreb, particularly in developing improvised explosive devices - "one of the main weapons of modern-day terrorism and particularly al-Qaeda".
There was also evidence that a significant number of Boko Haram members had fought alongside al-Qaeda affiliates in Mali, he said.
Quinlan said Boko Haram's current leader, Abubakar Shekau, also made "very, very strong statements of terrorist solidarity with al-Qaeda in Iraq, Afghanistan, Yemen, Somalia" and other places in November 2012.
Before Boko Haram's addition, the al-Qaeda sanctions list included 62 entities and groups, and 213 individuals who are also subject to travel bans.
Quinlan said it was hard to say what the practical impact of sanctions against Boko Haram would be. One possible problem in tracking their finances, he said, was that large parts of the group worked in the jungle and probably used cash rather than "substantial or sophisticated financial arrangements for banking - but you never know".
He urged all 193 UN member states to focus on Boko Haram as a violent al-Qaeda-related group, ensure that it was included in any national terrorist lists, and check their own country's financial and arms dealings to ensure that the organisation was not getting money or weapons.
Boko Haram's five-year-old Islamic uprising has claimed the lives of thousands of Muslims and Christians, including more than 1,500 people killed in attacks so far this year.
The group, whose name means "Western education is forbidden", has tried to root out Western influence by targeting schools, churches, mosques, government buildings and security forces. The homegrown terror group was largely contained to the northern part of Nigeria before expanding its reach with the help of al-Qaeda in the Islamic Maghreb, the terrorist network's affiliate in West Africa.
According to the sanctions committee, Boko Haram is responsible for attacks and kidnappings in Nigeria and Cameroon and has also been active in Chad and Niger.
Last Saturday, Nigerian President Goodluck Jonathan said that Boko Haram was acting "clearly as an al-Qaeda operation". He had previously insisted for years that Boko Haram was a local problem.