REPUBLIKA.CO.ID, SANGIHE -- Chief of a navy base in Tahuna, Sangihe Col. Setiyo Widodo said the navy is closely watching the sea border between Indonesia and the Philippines from its outpost in North Sulawesi's outer island.

"The navy intensified patrol for security in the sea border with the Philippines," the colonel said in Tahuna on Thursday.

Sea patrol has been a routine duty, but with what is happening in the Philippines it is necessary to intensify security patrols, he added.

The Philippine government is launching large scale military attack in a bid to drive Islamic militants from the city of Marawi in southern part of that country.

The militants which are affiliated to the Iraq and Syria Islamic State (ISIS) took over control of Marawi in May, 2017.

Setyo Widodo said the intensified patrols are to forestall possible infiltration of the terrorists fleeing Marawi into Indonesian territory.

He said the navy coordinated with the army and police in the regency of Sangihe to guarantee security in the district, adding the people have also been told to report any suspicious people or movements to the security authorities in the border areas.

Fishermen make up most of the people of the district that they could be relied on for information about suspicious movement in the sea and coastal areas, he said.

He said all people should continue to do their routine as the security apparatuses will always be ready for their protection.

The report about crisis in the neighboring country does not necessary affect their routine activities of going to the sea, he added.

Meanwhile, police's Mobile Brigade Corps had been sent to the border area in Northern Gorontalo and North Sulawesi to prevent fleeing terrorist from crossing the border to the region.

Report said that U.S. special forces had joined the Philippine military in the effort of freeing Marawi from the terrorist and saving thousands of civilians trapped in the the besieged city.

Gorontalo police chief Brig.Gen. Rachmad Fudail, said on Wednesday the patrol border is to prevent the terror to spread to Indonesian territory .

"Gorontalo is one of the closest Indonesian regions to southern Philippines. It is not impossible that the ISIS fighters crossed the border to Indonesia to escape," he said.

Chief of the Gorontalo police's Mobile Brigade corps Sr. Com. Kamaruddin said a troop of Mobile Brigade corps had been dispatched to the border area to help guarantee security in the region.

The Indonesian government has expressed concern about the conflict in Marawi. ISIS sympathizers already showed their presence in the country including by suicide bombing attacks.

Reports said almost the entire population of about 200,000 have fled the city, but beyond the checkpoints fencing it off there are still hundreds of civilians who cannot get out due to the violence or are being held hostage.

As of Saturday the number of security forces killed in the battle for Marawi stood at 58, while the death toll for civilians was 20 with more than 100 killed overall.

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