Three small foreign planes entering Indonesia's airspace without proper clearance have been intercepted by its air force jets in the past two weeks, while at least five boats have been detained over the past week for entering Indonesian waters illegally.
The spike in such incidents has led observers to raise questions about their timing, as they occurred so soon after the leadership transition. Several commentators went as far as to speculate that foreign parties were testing Indonesia's defences.
Some observers saw it possibly as a case of Jakarta getting tough and enforcing regulations strictly under new President Joko Widodo, while others believed it was a show of force by the military to get the government's support for more resources to secure the country's air and sea borders.
Dr Bantarto Bandoro from the Indonesian Defence University said the show of force could also mean that Indonesia might have installed new detection equipment to track such incursions.
"It is hard to tell the real intention of those who commit a breach. They could have wanted to test our radar, or they might have accidentally entered our territory," he told The Straits Times.
"If we didn't have good equipment, we could have missed it."
On Monday, a plane carrying Saudi officials en route to Brisbane was intercepted by two Sukhoi air force jets from a base in Makassar after it entered Indonesian airspace without proper clearance.
Two weeks ago, a light plane with two Australians on board was intercepted while it was flying to the Philippines. The aircraft was forced to land at Manado in North Sulawesi province. The Australians were later fined 60 million rupiah (S$6,600).
Last week, an ST Aerospace plane used for pilot training was likewise made to land at Pontianak in West Kalimantan. The three crew members were also fined 60 million rupiah.
On Wednesday, Air Chief Marshal Ida Bagus Putu Dunia refuted suggestions of a political motive behind the interceptions, insisting that the military was just doing its job.
His remarks came as critics at home voiced scepticism over the actions, noting that the air force did not take any action during similar incidents in the past.
"There is no political motive... it is the professional task of the air force to guard the sovereignty of our country's airspace," Marshal Ida Bagus told reporters.
Defence Minister Ryamizard Ryacudu pointed out that the fines imposed for such breaches were too low compared with the cost of activating air force planes to pursue intruders.
The former army chief promised to strengthen the radar capabilities of the air force.
He also noted that the country's navy faces obstacles when patrolling Indonesian territory.
Last Friday, a boat sailing from Pasir Gudang in Johor to Batam was detained, as were three Vietnam-registered boats, for illegal fishing off the Natuna islands. In the most recent incident, a Thai-registered vessel was detained on Monday.
Vice-President Jusuf Kalla praised the quick response.
"We intercept, we succeed. Our capability is good," he said at the opening of a defence exhibition.
International law expert Frans Hendra Winarta told The Straits Times that Indonesia's vast size and strategic location between Asia and Australia made its territory vulnerable to incursions if not guarded well.
Dr Bantarto said increased surveillance would be welcome as the country boosts its vigilance against the threat posed by militant groups such as the Islamic State in Iraq and Syria (ISIS), noting that Indonesia's porous sea borders are challenging to patrol. He suggested that Mr Joko could have ordered patrols to be stepped up, adding that the reason would not be disclosed to the public.
University of Indonesia academic Makmur Keliat told The Straits Times that acts of trespass into Indonesian waters draw less attention than intrusions into its airspace.
"Illegal fishing or piracy, the motive is economic. But airspace violations mean that a foreign nation or individuals are not respecting our borders."
This article was first published on November 7, 2014.
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