By Ainur Rohmah

TUBAN, Indonesia

Indonesia’s vice president announced Sunday plans to establish military cooperation and joint patrols with the Philippines and Malaysia, following a spate of kidnappings by armed groups operating in the seas between the archipelagoes.

The proposal comes after unidentified gunmen abducted four Indonesians from a tugboat off the southern Philippine island province of Tawi-Tawi -- where the Abu Sayyaf militant group and affiliated kidnap-for-ransom gangs operate.

"The traffic should be maintained by the joint patrol between Indonesia, Malaysia and the Philippines," kompas.com quoted Jusuf Kalla as saying.

He added that the plan had been presented to President Joko Widodo and received his approval.

Meanwhile, the coordinating minister for political, legal and security affairs said that Widodo had requested him to “explore joint security cooperation with Malaysia and the Philippines”, according to national news agency Antara.

Luhut Binsar Panjaitan underlined that the government is still working to identify the kidnappers, who authorities believe had economic motives rather than political.

"We're not sure yet if [the kidnappers are] pure Abu Sayyaf or its factions," he said.

Referring to Jakarta’s offers to assist the Philippines in tracking those responsible, the minister said Indonesia’s military had not received permission to enter the territory of its neighbor.

“The Philippine constitution does not allow for it, there must be consent from parliament," Panjaitan added.

In late March, 10 Indonesian sailors were seized off Tawi-Tawi, with their captors -- believed to be the Abu Sayyaf -- later demanding a ransom of 50 million pesos ($1 million).

In early April, Filipino gunmen selected four men from a Malaysian boat's crew and kidnapped them off the Malaysian state of Sabah, whose eastern coast is located just around 50 nautical miles from Sitangkai island in Tawi-Tawi.

Indonesia’s military chief said Sunday that the armed forces would coordinate with their Philippine and Malaysian counterparts to reach an agreement about joint patrolling in the piracy-prone region, where vessels such as oil tankers have been hijacked.

"If Indonesia and the Philippines undertake an MoU [memorandum of understanding] to conduct coordinated patrols, the trade route should be secure.

But it is not safe now because it is beyond our territory,” detik.com quoted Gen. Gatot Nurmantyo as saying.

"As army commander, I have prepared troops for decisive action at sea, on land, or in the woods. We are ready," he underlined. "We have deployed two warships, Badau and Slamet Riyadi, to the border area."

Kidnap-for-ransom gangs frequently operate in the Philippines’ Zamboanga Peninsula and the provinces of Sulu, Basilan and Tawi-Tawi.

They are known to hand over their captives to the Abu Sayyaf and negotiate for a ransom that, if paid, is shared with the group.

The kidnappers use isolated sea-lanes and coastal areas to grab their victims, who are then held captive in isolated villages in the peninsula.

Since 1991, the Abu Sayyaf -- armed with mostly improvised explosive devices, mortars and automatic rifles -- has carried out bombings, kidnappings, assassinations and extortion in a self-determined fight for an independent Islamic province in the Philippines.

It is notorious for beheading victims after ransoms have failed to be paid for their release.