Thai troops have opened fire on a fortified encampment of anti-government protesters in central Bangkok, and begun smashing down barricades, after days of bloodshed.
"The government has chosen to decisively enforce the law. The signals are that absolutely the army will win, but the losses will be unbearable.
"Certainly based on all the signs that I have seen there will be a crackdown, not a containment," he said.
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That decision left Red Shirt leaders calling on their followers to prepare for a fight.
"We're asking everybody to be ready for a crackdown because armoured personnel carriers are beginning to move in (to the area)," said Nattawut Saikua.
Local hospitals are said to be on full alert in case of further clashes between the army and protesters who have occupied a number of sites around Bangkok for the past six weeks.
Warning to stay off streets
There are reports the US embassy in Bangkok has warned its citizens to stay off the city's streets because of the heavy military presence.
Security forces have battled with protesters since last Thursday, attempting to seal off the sprawling protest site, and triggering clashes on the perimeter that left 39 dead and hundreds injured.
The violence, which eased on Tuesday with only sporadic gunfire, turned parts of the city of 12 million into no-go zones as troops used live ammunition against protesters, who fought back mainly with homemade weapons.
There are still about 5,000 protesters - including hundreds of women and children - at the fortified site despite the fighting and a campaign for them to return home.
Many of the women and children in the cordoned off protest area are believed to have taken shelter in the Pathum Wanaram temple.
