A massive security operation is underway before the Asian Games ©Getty Images

Almost 40 suspected terrorists have been arrested in the West Java region in the build-up to the Asian Games in Jakarta and Palembang, it has been announced.

West Java police confirmed that they had arrested "at least" 37 suspected terrorists, according to the Jakarta Post, as part of counter terrorism measures in the build-up to the Games.

Most of those under investigation are reportedly part of banned terror network Jamaah Ansharut Daulah (JAD).

The network are a splinter group of Jemaah Islamiyah, the organisation responsible for the Bali bombing in 2002.

"We carried out proactive measures against the JAD, which has the potential to commit acts of terror," said West Java Police chief inspector general Agung Budi Maryoto after leading a seminar for Asian Games security in Bandung.

The arrests were made between May and August across different towns in the province.

Five sports are due to take place in West Java during the Asian Games.

Indonesian police conduct an anti-terror drill ©Getty Images
Indonesian police conduct an anti-terror drill ©Getty Images

These are football, paragliding, modern pentathlon, canoe slalom and mountain bike and road cycling. 

Indonesia will employ 40,000 troops and police officers during the Games, which Jakarta is co-hosting with Palembang in Sumatra between August 18 and September 2, to prevent street crime and potential terrorist attacks.

Another 10,000 police officers will be on standby in Jakarta, while hundreds of closed circuit television surveillance cameras have been installed inside and outside sports venues.

There will be 40 sports, 67 disciplines and 465 events, with a record number of athletes - 11,300 from 45 National Olympic Committees - due to take part in the Games.