Indonesian police were hunting for Islamist militants Friday after terrorist attacks in the capital killed two civilians, as security was tightened across the country.
Five men armed with explosives and handguns attacked a police post and a Starbucks cafe near the Sarinah shopping center in the heart of Jakarta on Thursday, killing one Canadian and an Indonesian.
Two of the attackers blew themselves up while the other three died in a shootout with police, officials said. Twenty people were injured, including one each from Germany, Austria, Algeria and the Netherlands.
"We are in the pursuit of other cells and actors," Jakarta police chief Tito Karnavian said.
National police spokesman Anton Charliyan said authorities across the country were on the highest alert.
"Security has been beefed up in government offices, police stations, embassies and malls," he said.
Tito blamed a group led by Bahrun Naim, an Indonesian militant who is now thought to be in Syria fighting alongside the Islamic State group.
Bahrun celebrated the November Paris attacks in a blog post and encouraged militants in Indonesia to do the same.
Tito said Bahrun had instructed operatives in Indonesia to attack police and places frequented by Westerners on Christmas and New Year's Eve.
The police chief also said some of the attackers had been identified, but did not give details, state-run Antara news agency reported.
Jakarta police spokesman Muhammad Iqbal said three people arrested on the city's outskirts early Friday were not linked to the attack, but were questioned for alleged extortion.
Police in the city of Balikpapan in East Kalimantan province said they had arrested one suspected militant, but it was not clear if he was related to the Jakarta attack, Antara said.
President Joko Widodo said on Twitter that "there is no place for terrorism in Indonesia."
"All citizens of the world must unite to fight it."
Islamic State claimed responsibility for the attack, the militia's news agency al-Amaq said.
"A platoon of the Caliphate soldiers in Indonesia targeted in Jakarta a crowd of citizens from the Zionist alliance that fights Islamic State," it said.
The post claimed that at least four gunmen with light weapons and explosive belts killed at least 15 people.
The authenticity of the post could not be verified independently.
European Union foreign policy chief Federica Mogherini said the attack was "tragic reminder that the threat of terrorism is global and has to be tackled globally."
Indonesia has faced problems in recent years with extremist violence, often linked to Islamist groups, and it is estimated that hundreds of its citizens have joined the Islamic State group in the Middle East.
Police last month arrested nine suspects they said were planning coordinated attacks on New Year's Eve.