"The presidency of the EU condemns today's bomb attacks in Jakarta that have killed and injured so many innocent people," the Swedish government, current holder of the European Union's presidency, said in a statement.

"The EU conveys its deepest sympathy and condolences to the families of the victims of these brutal acts. We stand in sympathy and in solidarity with the Indonesian government and the Indonesian people in this most difficult time," the statement added.

US Secretary of State Hillary Clinton, en route to Asia for talks in India and Thailand, condemned what she called the "senseless" attacks, underlining that the threat of terrorism remains "very real".

"We condemn these senseless acts of violence and stand ready to provide assistance if the Indonesian government requests us to do so," she said. "The attacks reflect the viciousness of violent extremists, and remind us that the threat of terrorism remains very real," Clinton said.

In Paris, the French government said it condemned the double attack "in the strongest terms" and offered the victims' families and the Indonesian government its support and solidarity.

"France stands by the side of Indonesia, a major partner for our country in Asia, in its courageous fight against terrorism," the foreign ministry said in a statement.

France "offers its full support to the determined efforts of the Indonesian authorities to promote the stability of this great democracy," it said.

Australian Prime Minister Kevin Rudd said the blasts, in which at least two of his countrymen were wounded, made him "sick to the stomach".

"Any attack anywhere is an attack on us all," Rudd told reporters. "Any terrorist attack on our friends Indonesia is an attack on our neighbors. Any terrorist attack is an act of cowardice. It is an act of murder. It is a barbaric act that violates the fundamental principles of human decency."