Workers at the South Sudan Civil Aviation Authority at the Juba International Airport are threatening to strike on Tuesday if their demands are not met, according to a letter obtained by Radio Tamazuj.

The strike threatens to cripple national, international, and U.N. flights that come from the Juba International Airport.

The letter listed a number of grievances that include no holidays, no pay for four months, and a lack of medical allowances. The letter also demanded forty percent of total revenues generated from the Juba International Airport.

It was not immediately clear if the entire staff at the Juba International Airport supported the strike, or who the leader of the strike was.