Mauritania recalled its ambassador to Bamako on Monday in protest at Mali's release of four militants in an apparent exchange for a French hostage held by Al-Qaeda. 'Mauritania, while expressing its condemnation and rejection of this measure, has decided to recall its ambassador to Bamako for consultation,' Mauritania's foreign ministry said in a statement. Mali overnight Sunday freed four Islamic prisoners whose release was a key demand of Al-Qaeda militants threatening to kill a French hostage, a Malian security source told selfnews. The ministry said the decision to release the men was 'surprising' given that a Mauritanian among them was wanted by judicial authorities in Nouakchott. 'This non-cordial measure taken by the Malian authorities harms age-old relations between the two countries. 'Above all it's a flagrant contradiction of judicial cooperation accords and security coordination agreements,' between the neighbours, the ministry said. A Malian security source suggested to selfnews that Mali had not bowed to Al-Qaeda's demands as the men had completed their nine-month prison terms. Al-Qaeda in the Islamic Maghreb (AQIM) had demanded their release in exchange for French hostage Pierre Camatte, extending a previous deadline to February 20 and threatening to kill him if their demands were not met. While Mali's government had long insisted it would not give in to the demands, the four prisoners were last Thursday handed sentences which corresponded with the amount of time they had been in custody since their arrest in April 2009. The Malian security source said it could be still be several days before the Frenchman is freed. 