Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Thai 'Yellow Shirts' Stage Counter-Protests in Bangkok VOA News 29 April 2010 Pro-government supporters carry Thai national flags and sing nationalistic songs in Bangkok, Thailand, 29 Apr 2010 Photo: AP Pro-government supporters carry Thai national flags and sing nationalistic songs in Bangkok, Thailand, 29 Apr 2010 Thailand's pro-government activists staged a rally Thursday at an army base in Bangkok, demanding a government crackdown on their political opponents' nearly two-month old protest in the capital. The so-called Yellow Shirts rallied in front of the army base where Prime Minister Abhisit Vejjajiva has been living and working since the Red Shirts began their demonstrations last month.  They presented a petition to one of Mr. Abhisit's aides, calling on the prime minister to declare martial law and dispatch troops. They say the Red Shirts' protest is "illegal activity" that has damaged Thailand's economy and society. The Yellow Shirts claim to have staged rallies at 40 other military bases across the nation. The political crisis took another deadly turn Wednesday, when Thai security forces shot at a large group of Red Shirts heading towards a suburban market on pickup trucks and motorcycles. One soldier was shot and killed during the confrontation, apparently by friendly fire, while 18 others were injured.  At least 27 people have been killed and nearly 1,000 wounded since the Red Shirts began demonstrating in Bangkok last month. The protesters have brought the capital to a virtual standstill in their drive to force Mr. Abhisit to call new elections. The Red Shirts, made up mostly of the rural poor and urban working class, support former Prime Minister Thaksin Shinawatra, who was ousted in 2006 on allegations of corruption. They say Mr. Abhisit was installed in office illegally. The United States has urged all of its citizens to avoid all non-essential travel to Thailand because of the ongoing political crisis.  Some information for this report was provided by AP and AFP. .