Monday's car crash at Tiananmen Square was an act of terrorism by suspects from the Xinjiang Uyghur Autonomous Region, the Beijing police said on Wednesday, as it arrested five people, all of whom were allegedly involved.
The police described the incident as a "carefully planned and organized" attack by religious extremists from Xinjiang.
Usmen Hasan drove a jeep that had a license plate from Xinjiang, on Monday noon to "deliberately" plow through crowds, mainly tourists, along Chang'an Avenue where it runs through the Square, before crashing the vehicle outside the Tiananmen rostrum, killing two people and injuring 40.
Hasan's mother and wife were inside the vehicle as he drove before they triggered a blaze in which all three died in an apparent suicide mission, the police said.
Police found "gasoline, equipment full of gasoline, two knives and iron sticks as well as a flag with extremist religious content on it" in the charred vehicle.
Police also found knives and a jihadist flag at the temporary residence of the five detained suspects.
The detained suspects admitted to collaborating with Hasan to launch terrorist strikes and did not expect they would be captured just 10 hours after the incident at Tiananmen Square, police said.
Experts warned that the attack in the center of Beijing indicates a major shift of terrorist activities in China, which until recently were limited to northwestern Xinjiang as a result of the influence of the radical East Turkestan Islamic Movement.
"The whole nation should be on high alert of terrorist attacks, which can cause more fatalities in spite of the fewer number of participants," Li Wei, an anti-terrorism expert with the China Institutes of Contemporary International Relations, told the Global Times.
Li called counter-terrorism an arduous job and said "terrorists" will not be contained completely even in the future.
Turgunjan Tursun, a Uyghur scholar from the Xinjiang Academy of Social Sciences, told the Global Times that the attack is significant to China's counter-terrorism plans and the Xinjiang issue could become more complicated in this context.
He suggested that it remains a task for local authorities to improve the economic situation in Xinjiang in order to contain terrorism that is often bred from poverty and lack of education.
Authorities have found most terrorist suspects to originate from less developed areas in southern Xinjiang.
Li also praised the authorities' swift move to inform the public of the attack at Tiananmen Square.
A brief account of the fatal incident was released online within two hours of the incident on Monday. More details emerged on Wednesday.
Police issued two notices to hotels in Beijing after the attack, with the first one on Monday asking hotel management to look out for two suspicious guests and four car plates that originated from Xinjiang.
A staffer surnamed Liu from Legendale Hotel in downtown Beiing's Wangfujing area confirmed that they received another notice on Tuesday asking to look out for eight suspects and five vehicles with Xinjiang plates.
As of Tuesday, five people injured by the attack had already received operations, while 12 remained in intensive care due to their critical health condition, according to news portal qianlong.com.
One of the killed pedestrians was a female visitor from the Philippines. Two other Filipino tourists were injured.
The Philippines Embassy told the Global Times on Wednesday via e-mail that their priority is to offer consular assistance to the Filipino victims and they would continue to coordinate and make representations with relevant authorities on matters of concern to the victims.
"The embassy is extending its utmost assistance to the relatives of the victims who have arrived in Beijing," wrote Evangeline Ong T. Jimenez-Ducrocq, minister and consul of the embassy.