Indonesian immigration chief Hendarsam Marantoko said the government was reassessing visa waiver arrangements following a surge in cases involving foreign nationals allegedly engaged in cyber fraud, online gambling and other illicit activities.

Authorities last week detained more than 500 suspects in two separate operations targeting an online gambling syndicate in Jakarta and a scam network in Batam in the eastern Riau Islands province, officials said.

Those arrested included nationals from Vietnam, Cambodia, Malaysia, Laos and Myanmar, all of which currently benefit from Indonesia’s 30-day visa-free entry scheme. Chinese nationals were also among those detained, although China is not covered by the waiver policy.

“Cases of foreigners involved in illegal activities, including those coming from countries granted visa-free entry facilities, give rise to evaluation” of existing policies, Hendarsam said in a statement released by immigration authorities.

Investigators found that many suspects linked to the Jakarta gambling operation had entered Indonesia either under visa-free arrangements or through permits issued on arrival, according to officials.

Indonesia has intensified immigration enforcement in recent weeks as authorities seek to curb transnational cybercrime and illegal online betting operations, which have proliferated across parts of Southeast Asia.

Hendarsam said immigration authorities had conducted more than 6,700 administrative enforcement actions in recent weeks, including over 2,000 deportations and revocations of residence permits tied to immigration violations and criminal investigations.

Southeast Asian governments have faced mounting pressure to crack down on cross-border scam compounds and online gambling syndicates, many of which operate through regional networks involving foreign workers and digital financial transactions.

Government spokesman Minoru Kihara said the Japanese embassy in Iran had verified the release and that Japan’s ambassador had met the individual in person after their detention ended.

“The Japanese embassy in Iran has confirmed that a Japanese national who was detained by Iranian authorities on January 20 was released on April 6 local time,” Kihara told reporters, adding the individual’s health condition had been confirmed as stable.

Japan’s NHK was reported by Kyodo News to have identified the detainee as its Tehran bureau chief, although the broadcaster did not immediately confirm the report when contacted.Media reports earlier said the individual had been transferred to a prison known for holding political detainees following their arrest in January.

Japanese officials had previously acknowledged the detention but declined to provide further details at the time.

The release marks the second such case in recent weeks, after Tokyo announced last month that another Japanese national had been freed by Iranian authorities.

The man, identified by police as Luzian Andrin Zgraggen, was detained on Saturday after being reported over an Instagram post in which he allegedly used repeated expletives to refer to Nyepi, Bali police spokesman Ariasandy said in a statement late Sunday.

Zgraggen is being investigated for spreading hate speech online, an offence under Indonesia’s updated criminal code that carries a maximum penalty of five years’ imprisonment.

Police said they would confiscate his iPhone as part of the inquiry and question witnesses.Ariasandy did not specify the suspect’s age, in line with common Indonesian practice where some officials use a single name.

Nyepi, observed last Thursday on the island of Bali, is a key religious observance in the Hindu-majority region. The day requires residents and visitors to remain indoors for 24 hours for self-reflection, with work, travel, entertainment and even the use of electricity largely halted.

Indonesia, the world’s largest Muslim-majority country, has stepped up enforcement against behavior deemed offensive or unlawful by foreign visitors.

Bali, a major tourism destination attracting millions of international tourists annually, has seen a series of high-profile incidents involving foreigners in recent months.Last week, authorities arrested two French nationals and an Italian on allegations of producing and distributing pornography, which is prohibited under Indonesian law.