Indonesian Foreign Minister Retno Marsudi confirmed that 13 crewmembers of the tugboat Charles 001 and the barge Robby 152 were kidnapped in two ambushes conducted by an armed group in the Sulu Sea. Six of them have been released. The kidnapping, believed to be conducted by the Islam extremist group Abu Sayyaf, was the third abduction of Indonesians in the last three months. After the incident, the Indonesian Ministry of Transport issued a notice prohibiting authorities of all habours from issuing permits to Indonesian-flagged vessels bound for the Philippines. Sea Transport Director General at the ministry A. Tonny Budiono stressed that the kidnapping issue has become very serious and cannot be tolerated anymore. He said Indonesia will increase patrols in its waters bordering the southern Philippines. The Sulu and Celebes Seas form a key maritime route between Indonesia, the Philippines and Malaysia. Each year, 55 million tonnes of goods and over 18 million people are delivered through the areas.Last month, the three countries agreed to conduct joint sea patrols after a series of abductions.