The military was called in, and tanks rolled down Rajdamnoen Avenue and helicopters fired down at Thammasat University. A number of students commandeered buses and fire engines in an attempt to halt the progress of the tanks by ramming into them. With chaos on the streets, King Bhumibol opened the gates of Chitralada Palace to the students who were being gunned down by the army. Despite orders from Thanom that the military action be intensified, army commander Kris Sivara had the army withdrawn from the streets.