The International Committee of the Red Cross (ICRC) said it had not had direct contact with three of its staff abducted last month in the Philippines for more than a week. The hostages - Swiss national Andreas Notter, Italian Eugenio Vagni and Filipina Mary Jean Lacaba - were abducted on Jan. 15 during a humanitarian mission on the island of Jolo. Their kidnappers, thought by military officials to be members of the armed Muslim group Abu Sayyaf, had allowed the three hostages to talk on the telephone with the ICRC and their families one week ago. “Since then, we have not had any direct contact with them,” Alain Aeschlimann - who heads ICRC operations for East Asia, South-East Asia and the Pacific - said in a statement. “We are concerned about their health and about the fatigue and stress they are suffering,” he added. While there has been a lot of speculation, the ICRC said it did not know the exact whereabouts of the three. “All we can say at this stage is that we know they have been on the move over recent days and that they have had to walk in very difficult conditions, through the jungle and often in the rain,” Aeschlimann said. Aeschlimann says the Geneva-based Red Cross has learned from a reliable source the three have received medical supplies that were sent to them. The Red Cross is appealing to the abductors' sense of humanity and asking for their swift and unconditional release, he said. The humanitarian organization has not confirmed whether it was indeed Abu Sayyaf that kidnapped the three employees, who were visiting a prison at the time of their abduction. Abu Sayyaf once received funding from Osama Bin Laden's Al-Qaeda network, and is also on the US list of foreign terrorist organizations. The group has been blamed for the worst terror attacks in the Philippines, as well as for several kidnappings since 2000.