Bomb blasts tore through two luxury hotels Friday morning in Jakarta, Indonesia, killing at least nine people in what the country’s president called a “terrorist” attack.

Officials said more than 50 people were injured in the explosions at the Ritz-Carlton and JW Marriott hotels, which punched out the windows of a usually crowded restaurant and sent plumes of smoke into the sky.

President Susilo Bambang Yudhoyono said the bombings as the work of extremists.

“I condemn this terrorist attack,” Yudhoyono said. “I know they will never stop.”

One hospital reported that there were 16 foreigners wounded in the blast, Antara said. The victims were from the United States, Italy, South Korea, Japan, Norway, Netherlands, India, Australia and Britain.

Indonesia has been hit by several deadly bomb attacks targeting foreigners in recent years. More than 200 people were killed on the resort island of Bali in 2002 while 12 people were killed in a blast at the same Marriott hotel in Jakarta in 2003.

Those attacks were blamed on the Jemaah Islamiyah terror group, said to have links to Al-Qaeda.

Later Friday, police confirmed they had found an unexploded bomb in a room on the 18th floor of the Marriott Hotel.

No one has claimed responsibility for the attacks.

Police said the bomb at the Marriott likely came from the basement beneath the coffee shop on the ground floor, which would have been busy at breakfast time.

The U.S. State Department said several American citizens are among the injured.

“The State Department is working to help American citizens injured in the blasts,” Secretary of State Hillary Clinton said. “The attacks reflect the viciousness of violent extremists, and remind us that the threat of terrorism remains very real.”

Australian authorities said they had reports of at least two wounded Australians.

(Source: CNN)