In August 2003, a militant drove a bomb-laden truck into the lobby of the hotel and set it off, killing 12 people and injuring 150.

'The only group that has the ability to carry out such attacks is Jemaah Islamiyah,' terrorism expert Rohan Gunaratna told Channel News Asia.

Until Friday, Indonesia had not had a major bombing since October 2005 when militants belonging to Jemaah Islamiyah, a regional terrorist group affiliated with Al Qaeda, blew themselves up at three restaurants in Bali, killing 20 people.

Jamaah Islamiyah is also blamed for the October 2002 Bali bombings, which killed 202 people, mostly foreign holidaymakers.

Analysts have said that the group's violent faction has been severely weakened after the arrest of scores of operatives in recent years but determined militants were still capable of mounting a deadly attack.

Meanwhile, a car caught fire near a toll road gate in northern Jakarta, leaving two people dead, but it appeared to be an accident and unrelated to the blasts, Metro TV reported.

The hotel bombings came a little more than a week after the July 9 presidential election, in which incumbent Susilo Bambang Yudhoyono appeared set to win a second five-year term although the final results have yet to be officially confirmed.

Yudhoyono has been credited with restoring security after a spate of deadly attacks blamed on Jemaah Islamiyah since the start of the decade.

Presidential spokesman Andi Mallarangeng said Yudhoyono would make a statement later in the day.

'This is something very disconcerting,' Mallarangeng told Metro TV.

English Premier League champions Manchester United were due to stay at the Ritz-Carlton for their friendly match with an Indonesian All Stars side Monday.

It was not immediately clear whether the match would go ahead.