SINGAPORE - Twenty drone operators have been arrested in the last three months for illegally flying their drones within 5km of Changi Airport.

This is out of 44 such cases reported this year, said the Civil Aviation Authority of Singapore (CAAS) on Monday (Nov 23). It saw eight cases reported before July last year.

Disclosing the figures, the CAAS said measures to counter unmanned aircraft systems are being beefed up, after unauthorised drones twice disrupted airport operations in June last year.

These include putting in place specialised radars to better detect illegal drones.

In July last year, CAAS and Changi Airport Group set up an operations command and control centre to coordinate and integrate all counter operations against drones flown near the Changi aerodrome.

Illegal drones had caused significant disruptions to Changi last June. The first incident between June 18 and 19 caused delays in 37 flights and affected operations at one of Changi's two runways for short periods.

On June 24, a combination of unauthorised drones and bad weather delayed about 15 departure and three arrival flights, and caused another seven flights to be diverted.

There have been no intrusions leading to flight disruptions at the airport since July last year, said Senior Minister Teo Chee Hean on Monday, noting that the authorities had brought forward plans to enhance anti-drone capabilities at Changi.

"We have developed quite a reasonable capability, but this is a very challenging area and continues to evolve very rapidly because drone technology is moving very fast," he told reporters, adding that existing measures will continue to be improved.

In response to media queries, CAAS said the 20 errant operators were arrested for flying drones without permits within 5km of Changi Airport, including at areas such as Pulau Ubin, Changi Coastal Road, Pasir Ris Park, Bedok Reservoir and Tanah Merah.

Ground patrol forces have been stepped up to look out for such operators island-wide, focusing on hotspots identified, it added.

"CAAS takes a serious view of errant unmanned aircraft operations, and will not hesitate to take enforcement action against those who contravene the law."

The majority of unmanned aircraft offences involve operating them without the required permits, said CAAS, which is the lead agency overseeing the safe and responsible use of unmanned aircraft in Singapore.

A minority involved non-compliance to registration requirements.

CAAS said it adopts a "multi-layered approach" to ensure safe and responsible use of drones, ranging from education, regulation and registration to monitoring of critical areas as well as enforcement.

It works with other agencies in this effort, including the police, the air force, national water agency PUB, the Defence Science and Technology Agency, and the Maritime and Port Authority of Singapore.

Mr Teo, who is Coordinating Minister for National Security, on Monday visited one specialised radar near the airport's runway which was set up after June 2019.

The radar is among sensors installed to provide early warning of such illegal drone operations.

Reporters also saw officers carrying a radio frequency jammer and the ground enforcement officers who were deployed.

Mr Teo noted that drone intrusions are an evolving problem and a difficult one to resolve, with many airports in the world, including Singapore, trying and testing methods of countering them.

But the hope is that there is no need to catch anyone, he said. "We hope that drone operators will undertake upon themselves to operate drones in a safe way."