"Algerian army chiefs of staff on Monday afternoon formally denied information saying that the second group of hostages held by an armed group in the Algerian Sahara has been freed," the army said in a statement.

The statement called announcements "by the international media concerning the second group of hostages" mere "allegations", and said "the national army and security forces continue to make every effort to free them."

The army denial came after German security sources said the 15 tourists -- nine Germans, four Swiss and one Dutchman -- were no longer in the hands of their captors, and Germany's NTV television station reported they had been freed and were on their way to Algiers.

Last week, 17 tourists out of a total of 32 who went missing in the Algerian Sahara between mid-February and March were freed unharmed after the Algerian army raided the hide-out where they were being held near the southern Algerian city of Tamanrasset.

The release of the first group was reported initially by the Algerian and Austrian media and only hours later by the Algerian military, which had reportedly held back from any announcements amid fears it would endanger the lives of the 15 tourists still held captive.

The 32 missing European tourists had disappeared while travelling in separate groups without guides in Algeria's vast Sahara desert.

A report on Radio France Internationale on Friday said the release of the first group of hostages had been secured not by an army assault but was "linked to a ransom of several million dollars."

Algerian press reports over the weekend said the head of counter-espionage services, Samin Lamari, and German police had been trying to negotiate the release of the second group.

The remaining 15 hostages were reportedly being held in a mountainous region near Illizi, some 1,500 (930 miles) kilometres southeast of Algiers, near the border with Libya.

WAR.WIRE