Passengers queue for passing the security control atBarcelona's El Prat airport on August 11, 2017. ( AFP PHOTO/Josep LAGO)

MADRID, Aug. 13 (Xinhua) -- Security staff employed by the private company which has the concession to carry out security checks on passengers at Barcelona's El Prat airport on Sunday rejected the offer to end the conflict at will start an indefinite strike on Monday.

The workers, who are employed by the company, "Eulen" had previously rejected the offer of a 200 euros a month pay rise in a vote on Thursday and Sunday was the second time they turned the offer down.

The decision came on the fifth day of partial stoppages at Barcelona airport, which welcomed over 22 million passengers in the first six months of 2017.

The strikes again caused queues for travelers needing to pass through security in order to catch their flight, although the delays were shorter than on other days, lasting around half an hour.

Workers for Eulen have asked for a pay rise of 350 euros a month and retained their demands despite the announcement by the Spanish Ministry of Public Works to increase the presence of Civil Guards at El Prat to carry out baggage control and work alongside private workers boarding cards in checking boarding cards.

The Association of Civil Guards on Friday released a communique in which they criticized the decision saying the government had "decided to turn to badly paid Civil Guards to put an end to a private conflict."

Meanwhile, Purificacion Infante, a member of the Eulen strike committee lamented that the government was "very keen to destroy a strike, which is a constitutional right that we have."