Thai security forces have moved into the business district of Bangkok to block so-called Red Shirt protestors from taking their anti-government campaign to Thailand's capital's financial hub.
Thousands of military and riot police were deployed in the Silom business district close to the Reds' rally base in the capital's retail heartland.
Many of the security forces are armed with assault rifles and shotguns, wielding weapons and razor wire.
The deployment is the first by the military on the streets of Bangkok since a failed crackdown on the anti-government protestors nine days ago that left 25 people dead and more than 800 injured.
Army spokesman Sunsern Kaewkumnerd warned that the troops were equipped with live ammunition.
He said that the protest movement involving tens of thousands of red-clad demonstrators would be shut down 'when we are ready'.
'The authorities have their right to protect themselves. They will be armed with real bullets while they are on duty because we have to give them the ability to protect themselves,' he told AFP.
The Red Shirts, mainly supporters of former premier Thaksin Shinawatra who was ousted in a 2006 coup, have occupied parts of Bangkok for more than a month, causing massive disruption to business and tourism.
They had threatened to march to Silom tomorrow, but leader Nattawut Saikuar condemned the military operation and said they would now make a last-minute decision on where to direct their thousands of supporters.
'The reinforcements there are not normal. Soldiers have taken up positions where they are ready to fire at any time. They look like they are in the battlefield,' he told a press conference.
'We will analyse the situation to see if they are a danger to our people. But it would not be surprising if unarmed people walk there to invite the army to leave the area and return to their bases.'
Government spokesman Panitan Wattanayagorn would not comment on whether a crackdown was imminent against the Reds, who are demanding the ouster of embattled Prime Minister Abhisit Vejjajiva.
'The plan to retake the area remains, but operational units will analyse how and when to avoid confrontation and clashes,' he said.
Most businesses in Silom, a long thoroughfare packed with banks and corporate towers, remain open despite the intimidating military presence, but many workers and shoppers stayed away.
The Reds say that Abhisit's government is illegitimate because it came to power in a parliamentary vote, not a popular election, and that it is the tool of Thailand's elite in palace, military and bureaucratic circles.
A rival faction, the 'Yellow Shirts' who are backed by those elites, vowed yesterday to take matters into their own hands if the government fails to deal with the protestors within a week, raising fears of clashes.
The government says the crisis, which has crippled shopping centres and hotels in central Bangkok with days of closures, was costing Thailand up to $15m a day in lost tourism revenue.
