Dubai:
A statement posted on Tuesday on an Islamist website used by Al Qaeda threatened a strike at the "heart of Berlin" unless Germany releases a jailed female militant.
"This is a special message to the old lady of Germany (Chancellor Angela) Merkel... you should learn from what happened in France," said the unsigned statement on one of the group's main sites.
"Immediately release Um Seif Al-Islam Al-Ansariya before another Mohammed Merah strikes at the heart of Berlin," it added, reference to the gunman who murdered seven people in Toulouse, France in March.
Al Qaeda's North Africa branch, Al-Qaeda in the Islamic Maghreb (AQIM), says it is holding German engineer Edgar Raupach, kidnapped in Kano, Nigeria in January.
It wants to exchange him for Felis Lowitz, whose Muslim name was given as Um Seif Al-Islam Al-Ansariya.
"Many Muslims have heard about what you have done to Um Seif...you tore off her veil and tore off her clothes," said the statement, the first posting on Shamukh al-Islam website since it went offline, along with several other jihadist sites, more than a week ago.
Nigerian authorities have detained five men, including a Mauritanian, believed to be linked to the January kidnapping.