Several thousand opponents of Thailand's military-installed government marched through Bangkok's streets Saturday night to army headquarters, staging their most defiant protest yet against the regime that came to power after a coup d'etat last year. About 13,000 protesters gathered Saturday evening at Sanam Luang, an open field traditionally used for political protests, said Metropolitan Police Col. Manit Wongsomboon. A large part of the crowd then marched several kilometers to the military's headquarters. No violence was reported. Most in the crowd appeared to be supporters of former Prime Minister Thaksin Shinawatra, who was deposed in a bloodless Sept. 19 coup.