ANKARA

Private security staff of Barcelona's El Prat airport went on an indefinite strike Friday to demand better working conditions, according to a Spanish daily. 

El Mundo reported that the strike was called by some 500 guards on Thursday after a mediation meeting with the Trablisa security firm failed.

The firm has said it will have difficulty in securing a minimum service of 90% during the strike as demanded by the government.

The situation could complicate during the day as El Prat is in full summer season with a thousand flights scheduled for Friday.

The airport is facing the second strike in less than two weeks following Iberia Airlines's ground staff strike in late July.