BANGKOK – Anti-government protesters encamped for weeks in central Bangkok promised more aggressive measures after the government rejected their proposals to end increasingly violent protests in return for early polls. "Red-shirt" protest leaders called on their supporters in the countryside to confront the army and police. Their backers responded by blockading police convoys in at least two areas. The stalemate rekindled fears of more unrest and a heavier toll on Southeast Asia's second-biggest economy as more retailers shut their doors and tourist numbers dwindle. Prime Minister Abhisit Vejjajiva said he would soon scale back Thailand's annual economic growth forecast. About 500 km (310 miles) north of Bangkok, hundreds of "red shirts" formed a roadblock in northeastern Udon Thani province and stopped a convoy of 150 police from heading to the capital to strengthen security operations, a local official told Reuters. They formed another roadblock in Pathum Thani, about 50 kms (30 miles) north of Bangkok, preventing around 200 policemen from entering the city. Police reinforcements are being brought into the capital to forcibly disperse thousands of protesters occupying some central areas, said red shirt leader Jatuporn Prompang. "We will try to block every spot we can in a bid to stop killing. We don't want to see anybody die," he told Reuters. The army's failed attempt to eject red shirts from another site in Bangkok on April 10 led to clashes that killed 25 and wounded more than 800. Coming after red shirts stopped a troop train in the north last week, the blockade raises questions over whether Abhisit can exert full control over rebellious parts of Thailand as the deadly protests enter a seventh week. Abhisit, speaking on Sunday in a televised interview with army chief Anupong Paochinda in a show of solidarity with the military, flatly rejected a red shirt offer to call elections in 30 days and hold a vote 60 days later. "There must not be a precedent that allows intimidation to bring about political change," Abhisit said in his weekly television broadcast on Sunday. "Thirty days is out of question. I don't think this problem can be solved within 30 days." Hotel occupancy in Bangkok has crumbled to 20 percent from about 80 percent in February, squeezing an industry that supports six percent of the economy. Abhisit said he would soon scale back the government's projection of 4.5 percent annual economic growth this year. The army has had to deal with a rogue military element that supports the protesters and is allied with former premier Thaksin Shinawatra, who was ousted in 2006 coup and sentenced to prison for corruption after fleeing the country. The army chief sought to downplay signs of a split in the armed forces, but he acknowledged for the first time some retired and active officers had joined the protest movement.