JAKARTA — (CNN) Attackers struck in the middle of the day Thursday, in the middle of a busy central Jakarta commercial hub — killing at least two, wounding 19 and raising alarms about terrorism once more, this time in the world’s most populous Muslim country.

ISIS claimed responsibility for the attack in an official statement posted online by the terror organization, which was translated by the monitoring group Flashpoint and verified by CNN.

Jakarta police chief Tito Karnavian likewise blamed the Syria-based group and singled out a militant named Bahrun Naim, who he said plotted the attack to assert himself among various figures competing to lead ISIS in Southeast Asia. Police spokesman Anton Charliyan said Naim is in Syria but sent money back home to Indonesia to finance the attack.

One foreign national and one Indonesian make up the dead, authorities said. Charliyan said 24 people, including at least one more foreigner, were wounded.

The Jakarta carnage, in an area frequented by foreigners, came 6,000 miles from and two days after ISIS boasted about a suicide bombing in the heart of Istanbul. That attack in Sultanahmet Square, between the popular Hagia Sophia and Blue Mosque tourist attractions, killed 10 German visitors.

CNN security analyst Bob Baer likened the Jakarta attack to the November 13 Paris massacre in which terrorists linked to ISIS struck several locations at the same time. Yet the number of dead was nowhere near the toll of 130 in France, with Clarke Jones, a counterterrorism expert at Australian National University, calling it “fairly amateurish … with hand grenades and firearms.”

Another expert, Sajjan Gohel of the Asia-Pacific Foundation think tank, said it was particularly worrisome that this happened in the capital of Indonesia.

It was the first major attack in Jakarta since the 2009 simultaneous attacks on the J.W. Marriott and Ritz Carlton hotels, which left seven people dead. Since then, the secular government has made major inroads beating back terror groups in an Asian nation where about 87% of its roughly 255 million people are Muslim.

“It’s concerning (to have) yet one more day and another attack in another part of the world,” Gohel told CNN. “And one fears that this is potentially becoming the new normal where ISIS affiliates carry out attacks independently from the leadership based in Syria.”

‘We were so scared’

It began around 10:55 a.m. Thursday (10:55 p.m. ET Wednesday) with a suicide explosion near a Starbucks on Thamrin Street, an entertainment and shopping district with various Western chain restaurants and stores.

That set in motion two militants outside the coffee shop who seized two foreigners, dragged them into a parking lot and shot them, said Charliyan, the Jakarta police spokesman. They also opened fire at people on the street.

Heavily armed police soon swarmed the scene, firing on the militants and looking for other attackers.

The attackers responded by firing back and tossing two grenades at the officers, according to Charliyan. Minutes later, two more rode a motorcycle toward a nearby police post and blew themselves up.

Christian Hubel told CNN that he and his colleagues heard five or six explosions, one after the other. And Handi Kurniawan, who watched everything unfold from his office 20 floors above, called the ordeal “horrible.”

“We were so scared,” Kurniawan told CNN. “We just could not believe that this kind of thing (could) happen again in Jakarta.”

Dutch national among 19 wounded

The blasts and gunshots stopped by Thursday afternoon. And by nighttime, authorities were no longer hunting for attackers — though they are looking for those who helped them in plotting, financing and getting weaponry, Charliyan said.

By then, police had already counted five assailants dead at the scene. They also discovered several unexploded munitions, some of them high-grade explosives, at the scene, the police spokesman said.

There was conflicting information about the victims, with some officials putting the number of dead as high as six.

The ISIS statement claimed “nearly 15 Crusader foreigners” died in the attack, though there are no official reports indicating that’s true. The group said that its fighters “targeted a gathering of nationals of the Crusader alliance” — suggesting they were going after not Indonesians but citizens of other countries, many of whom have a role in the far-reaching campaign against ISIS.

It added that the operation was intended to “teach the citizens of the Crusader alliance that it does not protect them” or guarantee them “safety in the Muslim lands.”

Angele Samura, the security adviser for the Netherlands Embassy in Jakarta, said a Dutch national underwent surgery after being “severely injured.” It’s not known if this is the same Dutch citizen and U.N. Environment Programme worker who that agency reported was hurt.

Worries about ISIS fighters returning home

Jeremy Douglas, who works in the United Nations Office on Drugs and Crime in the area, said the location suggests if the terrorists “wanted to make an impact and get visibility … this is the place to do it.”

“You couldn’t get much more central in Jakarta if you tried,” Douglas said. “It’s basically right smack dab in the central business area.”

In recent weeks, Indonesian police have been on high alert, while military operations focus on hitting the East Indonesian Mujahadeen, helmed by Indonesia’s most-wanted terrorist, Santoso, who has pledged support for ISIS.

One major worry is that Indonesians fighting in Syria and Iraq will return home, having gained training and combat experience.

Yet many in the country acted more defiant than anything in the aftermath of Thursday’s attacks. Many went on Facebook and Twitter using #KamiTidakTakut — which translates to “We are not afraid” — to express their pride and conviction to stand up, rather than bow down, to terrorism.

“We are Indonesians & we never affraid to terrorist,” one man wrote. “We always fight anything that wanna take us down.”

This sentiment was echoed by President Joko Widodo.

“We should not be afraid and defeated by acts of terror like this,” he said.

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