AFP, Abuja :The United Nations imposed sanctions on Boko Haram Thursday, blacklisting it as an al-Qaida-linked terrorist organization as protesters stepped up demands on Nigeria to release 200 kidnapped schoolgirls.The terror designation, immediately welcomed by the United States, subjects Boko Haram to an arms embargo and asset freeze, though it remains unclear what practical impact it will have.The group, which demands the creation of an Islamic state in mainly Muslim northern Nigeria, has recently escalated its campaign of attacks that have left thousands dead since 2009.”Boko Haram are now listed on the United Nations’ al-Qaida sanctions list,” said Australian Ambassador Gary Quinlan, chair of the al-Qaida sanctions committee.”We will work to try and make sure that anyone providing material assistance to Boko Haram, whether funding or arms, will in effect be stopped,” he told reporters in New York.Quinlan said there was “very clear evidence” that Boko Haram had trained extensively with al-Qaida in the Islamic Maghreb, particularly on developing bombs.