President Barack Obama condemned the "outrageous attacks" on two hotels in the Indonesian capital on Friday, and U.S. officials said at least eight Americans were among those wounded in the suicide bombings.
None of the eight suffered life-threatening injuries, State Department spokesman Robert Wood said. All had been treated, and two were taken to Singapore for additional medical care.
"I strongly condemn the attacks that occurred this morning in Jakarta, and extend my deepest condolences to all of the victims and their loved ones," said Mr. Obama, who spent part of his childhood in Indonesia.
A U.S. official said Mr. Obama planned to call Indonesian President Susilo Bambang Yudhoyono.
Suicide bombers posing as guests attacked American luxury hotels in Indonesia's capital and set off a pair of blasts Friday that killed at least eight people and wounded more than 50, authorities said.
The bombings, which came two minutes apart, ended a four-year lull in terror attacks in the world's most populous Muslim nation. At least eight Americans were among the wounded.
The blasts at the highrise J.W. Marriott and Ritz-Carlton hotels, located side-by-side in an upscale business district in Jakarta, blew out windows and scattered debris and glass across the street, kicking up a thick plume of smoke. An Associated Press reporter saw bodies being carried away in police trucks.
The attackers evaded hotel security, smuggling explosives into the Marriott and assembling the bombs in a room on the 18th floor, where an undetonated device was found after the explosions. The bombers had stayed at the hotel for two days and set off the blasts in restaurants at both hotels.
"They had been using the room as their 'command post' since July 15, and today they were supposed to check out," police chief Gen. Bambang Hendarso Danuri said.
Alex Asmasubrata, who was jogging nearby, said he walked into the Marriott before emergency services arrived and "there were bodies on the ground, one of them had no stomach," he said. "It was terrible."
There were conflicting casualty counts - some reports indicating nine deaths, while others said the total was eight.
The attack occurred as the Marriott was hosting a regular meeting of top foreign executives at major companies in Indonesia organized by the consultancy firm CastleAsia, said the group, which is headed by an American.
An Australian think tank, the Strategic Policy Institute, had warned the Southeast Asian terrorist group Jemaah Islamiyah might launch new attacks just a day before Friday's deadly strike.
There was no claim of responsibility for the attacks.
Two of those wounded at the Ritz-Carlton were employees of Phoenix-based Freeport McMoRan Copper & Gold, Inc., said Bill Collier, a company spokesman. CBS News has learned that one of the employees is American, the other is Indonesian. Collier declined to release their names, citing company policy, but said their injuries were not life-threatening.
Freeport operates the world's largest gold mine in Indonesia's restive eastern Papua province. Several attacks have occurred in the past week on the road from the firm's sprawling Grasberg mining complex to the mountain mining town of Timika, leaving at least 15 people killed or wounded.
Authorities initially blamed the ambushes on Papuan separatists, but official statements now refer to "an armed group" of professional marksmen.
There was no claim of responsibility for the attacks, but terrorism analyst Rohan Gunaratna said the likely perpetrators were from Jemaah Islamiyah.
"The only group with the intention and capability to mount attacks upon Western targets is Jemaah Islamiyah. I have no doubt Jemaah Islamiyah was responsible for this attack," he said.
There was a crackdown in recent years by anti-terrorist officials in Indonesia, a predominantly Muslim nation of 235 million, but Gunaratna said the group was "still a very capable terrorist organization."
Police have detained most of the key figures in the Indonesia-based Jemaah Islamiyah and rounded up hundreds of other sympathizers and lesser figures.
Authorities did not immediately name a suspect, but suspicion fell on the Jemaah Islamiyah or its allies. The al Qaeda-linked network is blamed for past attacks in Indonesia, including a 2003 bombing at the Marriott in which 12 people died and the 2002 bombings of two Bali nightclubs, which killed 202 people.
Indonesian President Susilo Bambang Yudhoyono said the attack was carried out by a "terrorist group" and vowed to arrest the perpetrators. He also suggested a possible link to last week's national presidential election.
Secretary of State Hillary Rodham Clinton condemned the bombings as "senseless" in a statement issued from the Czech Republic, as she traveled on to India.
Mr. Obama and Clinton pledged U.S. support for the Indonesian government. They said attacks underscored the need to remain steadfast in the fight against violent extremism.
"We will continue to partner with Indonesia to eliminate the threat from these violent extremists, and we will be unwavering in supporting a future of security and opportunity for the Indonesian people," Mr. Obama said.
Clinton said the attacks "reflect the viciousness of violent extremists, and remind us that the threat of terrorism remains very real."
The European Union condemned the blasts.
The Manchester United football team canceled a visit to Indonesia in the wake of the attacks. The team had been scheduled to stay at the Ritz- Carlton on Saturday and Sunday.
Security is tight at five-star hotels in Indonesia. Guests typically walk through metal detectors and vehicles are inspected, but many visitors say searches are often cursory.
"If they (the terrorists) were to separate explosives and metals they could get through the detectors because the wands the hotels use do not detect explosives," said Jakarta-based security consultant Ken Conboy.
The Marriott was hit first, followed by the blast at the Ritz-Carlton.
Security Minister Widodo Adi Sucipto told reporters the explosions happened at 7:45 a.m. and 7:47 a.m. and that "high explosives were used." He said eight people were killed and 50 wounded.
"All of a sudden there was a huge explosion," Lydia Ruddy, who lives and works across the street from the Ritz, recounted to Early Show co-anchor Maggie Rodriguez. "As I walked up toward the hotel it was eerily calm. There were people starting to come out of the buildings, smoke was pouring out of the windows."
Security video footage shown on a local TV station captured the moment of the explosion in one of the hotels. The brief, grainy images show a man in a cap walking across the lobby toward the restaurant with other hotel guests and then smoke filling the air.
"There was a big explosion followed by a shock wave," said Ahmad Rochadi, a security guard at the Marriott who was checking cars in the basement. "I rushed upstairs and saw smoke billowing from the lobby."
Anti-terrorist forces with automatic weapons rushed to the site, and authorities blocked access to the hotels in a district also home to foreign embassies.
It has been nearly four years since a major terrorist attack in Indonesia - a triple suicide bombing at restaurants at the resort island of Bali that killed 20 people.
The security minister and police said a New Zealander was among those killed, and that 17 other foreigners were among the wounded, including Americans and citizens of Australia, Canada, Hong Kong, India, Italy, the Netherlands, Norway, South Korea and Britain.
The dead New Zealander was identified by his employer as Timothy David Mackay, 62, who worked for cement products manufacturer PT Holcim Indonesia. He was reportedly attending a business meeting at the Marriott.