Jakarta, Indonesia ? Attackers used a mobile phone to detonate the car bomb at Jakarta’s Marriott Hotel, the same method used by al-Qaida-linked bombers on the tourist island of Bali last fall, police said Wednesday.

Other similarities, including the use of the same types of explosives in both attacks, could connect the regional terror group Jemaah Islamiyah to the blast Tuesday that killed up to 14 people, authorities said.

Jemaah Islamiyah almost certainly carried out the bombing, a U.S. official in Washington said on condition of anonymity. The official said the blast had the hallmarks of previous attacks by the group, an Islamic movement that officials have linked to al-Qaida and blamed for the Bali bloodshed.

Officials warned more attacks were possible in the wake of the Marriott bombing, which also wounded nearly 150. Worries about the threat of terrorism have been high in the Southeast Asian archipelago, the world’s most populous Muslim nation.

Indonesian police also revealed that documents seized last month, during the arrest of seven alleged Jemaah Islamiyah members, indicated terrorists were planning to target the area around the Marriott. They said security forces had increased patrols in the neighborhood.

“There was a warning that there were some targets and we have been anticipating an attack,” said police spokesman Prasetyo, who like many Indonesians uses a single name.

Two of the alleged Bali bombers expressed happiness at the attack.

“Thank God. I am thankful,” Imam Samudra, the alleged mastermind of the Bali bombings that killed 202 people Oct. 12, shouted after he testified in Bali during another suspect’s trial. “I am happy, especially if the perpetrators were Muslims.”

One of his alleged accomplices, Amrozi bin Nurhasyim, grinned and yelled “Bomb! when asked about the Marriott attack, which came two days before a verdict in Amrozi’s own trial.

Jakarta police spokesman Col. Prasetyo holds up a sketch of a possible suspect in the Marriott Hotel bombing. The man pictured is one of two men who reportedly purchased the vehicle used to attack the hotel. Nno group has claimed responsibility but police think the terror group that attacked the resort island of Bali last year was also behind Tuesday's blast, which killed up to 14 people.

Indonesia’s chief of detectives, Erwin Mappaseng, said at a news conference that the Marriott bombers used a mobile phone to detonate the explosives, the same technique as in the Bali bombings. He said the phone was found in the wreckage.

Also like the perpetrators of the Bali bombers, the Marriott attackers used both TNT and RDX explosives, he said.

The national police chief, Gen. Da’i Bachtiar, said the Marriott bombers tried to sand down the serial numbers on the vehicle’s engine and chassis, just as was done in Bali. Police were still able to retrieve all the numbers, he said.

Mappaseng said it was too early to conclude the similarities provided a definitive link between the Marriott and the Bali attacks. But Bachtiar said those facts were leading police to focus the investigation on Jemaah Islamiyah.

Mappaseng said officers had found a badly burned head close to wreckage of the bomb vehicle. “We strongly suspect that (this person) is linked with the bomb,” he said.

Police also found two dismembered hands that could provide fingerprints of the suspected suicide bomber, Bachtiar said.

Health Minister Achmad Suyudi said Wednesday that 10 people were confirmed killed in the bombing and 147 people were wounded. The Indonesian Red Cross had said 14 people were killed but retracted that.

The Marriott, which faces a traffic circle that by Jakarta standards has light traffic, is about 150 feet from the street and has no gates at the entrance.

The suspected car bomb went off near the hotel’s front entrance beside an adjacent office building — probably around the point where security guards normally check vehicles entering and leaving.

Police released a composite sketch of one of two men who reportedly purchased the vehicle used in the bombing.

Indonesia’s economy is still reeling from the effects of the Bali bombings. It had recently been showing signs of bouncing back, but Indonesians worried Tuesday’s attack would bring another falloff in foreign investment and tourism.