Thai riot soldiers holding army shields take part in a practice at the Government House in Bangkok March 16, 2010. Tens of thousands of protesters pressed ahead with a mass rally in Bangkok on Tuesday, some expressing frustration that four days of peaceful protests had failed to force Thailand's premier to call elections. Early on Tuesday, leaders of the "red shirts" were collecting a vial of blood from each supporter which they intend to spill outside Abhisit's office in what they are calling a symbolic shedding of blood for democracy. (Reuters)

Thai riot soldiers wearing gas masks take part in a practice at the Government House in Bangkok March 16, 2010. (Reuters)