Opposition to his government grew during Castillo Armas's presidency. On Labor Day in 1956, members of the government were booed off a stage at a labor rally, while officials who had previously been in the Árbenz administration were cheered. The Guatemalan Communist Party began to recover underground, and became prominent in the opposition. Overall, the government had to deal with four serious rebellions, in addition to the coup attempt by the cadets in 1954. On June 25, 1956, government forces opened fire on student protesters, killing six people and wounding a large number. Castillo Armas responded by declaring a "state of siege", and revoked all civil liberties. On the advice of the US ambassador, the protests were portrayed as a communist plot.