Seventeen people were killed in Baghdad today when three suicide car bombs exploded next to a fortified hotel compound used by foreign journalists.

At least 15 more were injured when the bombs were detonated - two small blasts followed by a third massive explosion - beside the concrete towers of the Sheraton and Palestine hotels.

The attacks came amid mounting tension over the outcome to Iraq’s constitutional vote. The result is due to be released within hours, and with two provinces already confirmed to have voted 'no', the future of the draft constitution rests on a knife-edge.

"The victims are either security guards, hotel employees or passers by," a security source said. It is unclear if any foreigners were among the dead or injured.

Video images showed a cement truck had apparently breached the security perimeter for the Palestine and Sheraton hotels, followed by a massive explosion in that part of Paradise Square.

A shockwave was felt across the centre of the city and huge grey and black clouds billowed up from the buildings.

An AP photographer at a checkpoint near the hotel said at least 3 fellow photographers were injured and taken away by ambulance. Two TV personnel inside the hotel sustained minor injuries.

Television pictures showed a huge cloud of smoke rising from the scene and debris falling from the 19-storey hotel building.

After the bombing, Iraqi forces opened up with heavy automatic weapons fire, apparently at random.

AP journalists had to evacuate their bureau in the hotel and take refuge in the corridor. Inside the hotel, light fixtures were blown down, pictures were blasted off the walls and windows were shattered.

BBC correspondent Caroline Hawley said that the force of the explosions blew out windows in her office a couple of hundred metres away.

She said: "There were three large explosions within a few minutes of each other. There was quite a lot of confusion and panic in the immediate aftermath."

The hotels are close to Paradise Square where the statue of Saddam Hussein was symbolically toppled on April 9, 2003.

"It’s a very symbolic target right in the centre of the city," Hawley said.

"There is a lot of security surrounding the Palestine and Sheraton hotels but the square is a public square and cars drive through it all the time. I think the aim was to strike at the symbolic heart of this city and get as much attention as they could."

The fate of the referendum on Iraq’s draft constitution rested tonight on the still undeclared results of a single Sunni-dominated province, after a second region rejected the charter.

Electoral officials announced in Baghdad that volatile Al-Anbar province voted down the constitution in the October 15 referendum with 96.95 percent against, joining Salaheddin which rejected the results by 81.5 percent.

With a two-thirds majority against in three of Iraq’s provinces sufficient to torpedo the whole document, all eyes will now be on the eventual result in the Sunni-dominated "swing" province of Nineveh and its mixed capital of Mosul.

However election officials appeared relaxed as they kept the world on tenterhooks over the final outcome of the referendum.

"There is no problem in this province, the results are being verified and counted again, then we will issue the final result," said senior election official Abdul Hussein Hindawi.

"We don’t have a result yet we will get it later today and give it tomorrow."

The other three of the final four provinces - Arbil, Babel and Basra - are expected to overwhelmingly approve the charter.

With the constitution winning resounding support from Shias and Kurds, the only hope of Sunni Arabs to reject a charter they fear could hasten Iraq’s break-up is to muster the two-thirds majority in Nineveh.

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