© Antara Foto / Zabur Karuru / Reuters
Indonesia navy soldiers on warship and helicopter are seen during the launch of coordinated patrols to beef up security between Malaysia, Indonesia, and Philippine, Indonesia, June 19, 2017.
Indonesia, Malaysia and the Philippines have launched joint operations in the Sulu Sea off the north coast of Borneo, amid fears that the Islamist insurgency in the southern Philippines might spread throughout the region.

The Indonesian military said the joint maneuvers, which began on Monday from Tarakan island in North Kalimantan, Indonesia, were "in the spirit and centrality of ASEAN [Association of Southeast Asian Nations], in maintaining stability in the region in the face of non-traditional threats such as piracy, kidnapping, terrorism and other transnational crimes in regional waters," read a statement to the media as quoted by the Straits Times.

Ministers and top army officials from the three countries, as well as defense ministers from Brunei and Singapore, attended the ceremonies which kicked off the mainly naval-based operation, although land and air forces are taking part as well.

© Google Maps
A new Maritime Command Centre (MCC) was also inaugurated at Tarakan, at a ceremony witnessed by officials from all three countries. Tarakan is a port city just south of Borneo and facing the conflict-wracked island of Mindanao in the southern Philippines.

Additional command centers are also being planned in Tawau in Malaysia, on Borneo, and in Bongao in the Philippines.
"We see these functioning as a triangle, like a spider's web, where everything inside the triangle will be monitored," Indonesian military chief General Gatot Nurmantyo said as cited by Reuters.
There has been renewed concern over Islamist activity in south-east Asia, particularly after extremists overran the city of Marawi on Mindanao island, Philippines nearly a month ago.

The attack on Marawi was carried out by the IS-affiliated Maute group, which together with other extremist groups like Abu Sayyaf have been carrying out terrorist attacks in the region, as well as other crimes such as hostage-taking, extortion and piracy.

As the Philippine military lay siege to Marawi, jihadist fighters, both foreign and local, may try to flee the battlefield to Indonesia, which has intensified security in the sea between their country and the Philippines.
"We need to watch out for the 500 to 600 terrorists there, 257 of whom have been killed already. The rest, based on information we are getting, are blending in with refugees to get out," General Nurmantyo explained.
Jakarta has deployed three Sukhoi fighter jets to prevent the militants from infiltrating Indonesia by sea, the head of the Tarakan air base told the state-run Antara news agency.

Malaysia, Indonesia and the Philippines also pledged to increase intelligence-sharing to prevent another Marawi-type incident happening again, said Malaysian defense minister Hishammuddin Hussein.
"What we want to avoid is a development of perceptions that there are certain areas in our region that are seen as Aleppo, Raqqa (in Syria), meaning these areas would become magnets, to which foreign fighters would be attracted to come," said Hussein, as quoted by the Straits Times.

"We want to convey a very clear message that if they want to set foot here, they don't only face one country, but at least three countries that have agreed to fight as hard as they can."