Indonesia's counter-terrorism forces have been on high alert after detecting elements of domestic militants closing in on Jakarta.
Besides raising security alert levels, the country also tightened surveillance on citizens recently deported after trying to link up with the militant group Islamic State in Iraq and Syria (ISIS) via Turkey.
This comes as a series of crackdowns on terror suspects continues across France after the siege on Paris on Friday, which saw 129 people killed.
Inspector-General Arief Dharmawan, who is deputy head of enforcement at Indonesia's National Counter-Terrorism Agency (BNPT), confirmed that militant elements have popped up near Jakarta recently.
He said on Saturday that intelligence points to the presence of militants in suburbs such as Cileduk and South Tangerang, just an hour's drive from the capital.
"Militants in Indonesia are mostly lying low, but they are working and plotting," said Mr Arief. "South Tangerang and Cileduk have become new militant strongholds."
This was a re-emerging trend as most domestic extremists in recent times tend to operate outside the capital and in terrorist hot spots such as Poso in Central Sulawesi or Solo in Central Java.
Mr Arief said 162 Indonesians have been deported, mostly from Turkey, to date. Among them are 40 male adults, classified as men of fighting age, who have been released in their hometowns.
This is because there are no laws that allow for preventive detention in Indonesia even though some had intended to join terror groups.
The 40, however, have been interrogated by Detachment 88, Indonesia's crack counter-terrorism outfit made up of elite police officers specifically trained to fight terror, said Mr Arief.
These are also the same officers who form the surveillance teams dedicated to monitoring them, added the the two-star police general.
"Many Indonesians have gone to wage a jihad, being lured by a propaganda promising them 72 virgins if they die as a jihadist," said Mr Arief.
Observers, however, expressed concerns over the dangers these deportees pose when released.
"Men who join ISIS... have higher severity in their militant mindset, compared to those who support Al-Qaeda," said analyst Al Chaidar of Malikussaleh University.
Mr Robi Sugara, from Syarif Hidayatullah State Islamic University in Jakarta, also questioned whether Detachment 88 has the resources to stay on top of their targets.
He added that the authorities must rope in all relevant parties, including the national intelligence agency to monitor deportees.
Separately, sources told The Straits Times yesterday that a Batam civil servant who recently abandoned his post to join ISIS, had apparently done so after being pressured by his wife.
Mr Dwi Djoko Wiwoho, director of a licensing office in the Riau Islands, had supposedly gone to Mecca for umrah (minor haj) in late August. But the BNPT said this month that he and his family had arrived in Iraq and joined ISIS.
According to one of the sources, Mr Dwi's wife had persuaded him to quit his job and join the terror group.
Mr Rahmad said Mr Dwi had opposed his wife's radical views, which she developed after joining a Quran reading group. But he gave in after she threatened to take their children away to the Middle East.