'I was having a breakfast in the nearby restaurant when I heard a very strong blast,' said Intan, a local official.

'I saw several blooded foreigners taken out of the hotel,' she told the TV One channel.

Television footage showed ambulances continuing to arrive at the scene and there was a heavy police presence.

The blasts came just over a week after the July 9 presidential election, in which incumbent Susilo Bambang Yudhoyono appeared set to win a second five-year term in office although the result has not yet been officially confirmed.

Yudhoyono has been credited with restoring security following a spate of deadly attacks blamed on Islamic militants from the Jemaah Islamiyah radical group since the start of the decade.

It was a second bomb attack on the Jakarta Marriott. 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.