Indonesia has been on increased alert as the focus of the country's battle against terrorism shifts to Daesh sympathisers.

Police investigate the explosion at a bus station in Kampung Melayu, East Jakarta, Indonesia. (May 25, 2017)
Police investigate the explosion at a bus station in Kampung Melayu, East Jakarta, Indonesia. (May 25, 2017) ()

Indonesian police on Friday arrested three suspects in connection to attacks that killed three police at a Jakarta bus station this week, a spokesman said.

Yusri Yunus, head of public relations at West Java Police, said the arrests had taken place in Bandung, the capital of West Java province, without providing details

Daesh claimed responsibility for the attack that left the three policemen dead and 12 others wounded on Wednesday.

The officers were guarding a parade by a group of local people at the time of the attack.

Police said the assailants used pressure cookers packed with explosives.

Investigators at the blast site found a receipt for a pressure cooker bought on Monday in Bandung, the site of Friday's arrests.

The attack in the city's Kampung Melayu area was the deadliest in Indonesia since January 2016, when eight people were killed, four of them attackers, after suicide bombers and gunmen attacked the capital.

The government has carried out a sustained crackdown on militants since the 2002 Bali bombings by Al Qaeda-affiliated attackers that killed 202 people.

A new threat has emerged in the past several years from Daesh sympathisers.

While most recent attacks in Indonesia have been poorly organised, authorities believe about 400 Indonesians have joined Daesh in Syria and could pose a more lethal threat if they come home.

Police raids

Indonesia's anti-terrorism unit raided the home of a suspected suicide bomber on Thursday as authorities linked the Jakarta attacks to Daesh.

Earlier, a police spokesman told reporters that police were investigating whether the attackers had direct orders from Syria or elsewhere.

"After what happened in Manchester, in Marawi in the Philippines, maybe the cells here were triggered by the bombs and that lifted their passion to start bombing again," the spokesman told television station TVOne.

He was referring to a suicide bombing this week that killed 22 people in a crowded concert hall in the British city of Manchester.

In the southern Philippines, thousands of civilians have fled their homes after militants took over large parts of Marawi city, leading to a declaration of martial law.

Source: TRTWorld and agencies