A message purportedly posted by the Islamic State claimed responsibility for the attacks, according to the SITE Intelligence Group, which monitors militant websites. Earlier, a group with ties to the Islamic State, the Aamaaq news agency, posted an Internet message claiming the attacks were carried out by “Islamic State fighters.” The claims could not immediately be confirmed.
If verified, however, the Islamic State’s involvement would mark one of the group’s deepest reaches into Asia — and the capital of the world’s most populous Muslim nation — after spilling blood in North Africa, Europe and possibly Turkey with Tuesday’s suicide blast that killed 10 German tourists in the shadow of Istanbul’s famed Blue Mosque.
The Jakarta assailants appeared outfitted for a running siege: armed with handguns, grenades and homemade bombs, police said. They also followed tactics that have become a hallmark of recent urban terrorism — hitting targets with limited security.
The mayhem began with a suicide blast at a Starbucks coffee shop while gunmen outside opened fire, killing a Canadian man, said Jakarta’s police chief, Maj. Gen. Tito Karnavian. Moments later, two suicide bombers struck a traffic police post, killing themselves and an Indonesian man.
As police swarmed the area, the remaining attackers opened fire, touching off a 15-minute gun battle that left two assailants dead, Karnavian said. At least 19 people were wounded in the chaos that unfolded amid luxury hotels, shops and office towers.
Security forces later put the streets on lockdown, including areas near the U.S. and French embassies and other diplomatic sites.
Authorities said they found a large, undetonated bomb and five smaller devices in a building near the Starbucks, the Associated Press reported.
“So we think … their plan was to attack people and follow it up with a larger explosion when more people gathered,” said the police spokesman Charilyan. “But thank God it didn’t happen.”
He said the range of weapons and targets suggested an attempt to copy the Nov. 13 terror attacks across Paris that left 130 people dead.
Karnavian, the police chief, identified the suspected lead plotter as Indonesian fugitive Bahrun Naim, who is believed to be in the Islamic State’s Syrian stronghold, Raqqa. Naim is described as the leader of Katibah Nusantara, a Southeast Asian-based armed faction with Islamic State connections.
“This act is clearly aimed at disturbing public order and spreading terror among people,” Indonesian President Joko Widodo said in a televised address. “The state, the nation and the people should not be afraid of, and be defeated by, such terror acts.”
In London, Secretary of State John F. Kerry said “acts of terror are not going to intimidate nation-states.”
“We stand together, all of us, united in our efforts to eliminate those who choose terror,” added Kerry, who was holding talks with his Saudi counterpart, Adel al-Jubeir, amid the kingdom’s deepening tensions with Iran.
A National Security Council spokesman in Washington said in a statement: “The United States is strongly committed to our strategic partnership with Indonesia and will stand by the Government of Indonesia as it works to bring those responsible for this barbaric terrorist attack to justice and build a more secure future.”
Although Indonesian authorities seemed focused on apparent Islamic State links, the vast country is home to other suspected militant factions that have roots going back decades.
On Tuesday, a jailed radical Islamist cleric, Abubakar Baasyir, appealed to an Indonesian court to overturn his conviction for funding a terrorist training site in Aceh province in the country’s northwest. Baasyir’s group, Jemaah Islamiah, seeks Islamic-style rule and has suspected links to other Islamist factions around Southeast Asia.
Indonesia sharply bolstered its anti-terrorist codes and surveillance following bombings in 2002 at nightclubs on the resort island of Bali that killed 202 people, mostly foreigners. In 2009, militants in Jakarta staged suicide attacks at Marriott and Ritz-Carlton hotels, killing seven people and injuring more than 50.
Last month, Indonesian officials warned of a “credible threat” of an attack and brought out 150,000 security personnel to help guard churches, airports and other places, the Associated Press reported.
On Jan. 3, the U.S. Embassy in Jakarta warned Americans of “a potential threat” against U.S.-associated hotels and banks in Surabaya, about 500 miles east of Jakarta on the island of Java. The U.S. Embassy said it would remain closed Friday.
This report has been updated. An earlier version incorrectly said that six homemade bombs were found inside a Starbucks in Jakarta. The devices were found in a nearby building, the Associated Press reported.