BARCELONA, Spain — Workers handling carry-on luggage checks at Barcelona’s airport staged a second day of partial strikes Sunday, causing long lines for passengers at one of Europe’s most popular airports.

Passengers waited for up to an hour to pass security checks at El Prat airport at the peak of the midday worker slowdown, with waits then shrinking to 20 minutes, according to regional public broadcaster TV3.

The workers staged partial strikes Friday, leading to waits of 40 minutes.

More negotiations were held Sunday between workers’ representatives, the private company, Eulen, which runs the service at the airport, and regional government authorities.

Spain’s airport authority, AENA, said in a statement Saturday that there had been “advances in the negotiations, and the issue of worker salaries is the only one left to resolve.”

Workers plan to stage another partial strike Monday and have threatened to go on a non-stop strike starting Aug. 14.

Passengers flying from Barcelona have been suffering delays of several hours to reach the boarding area in recent weeks. The association of Spanish airline companies, ACETA, said last week that about 1,000 people have missed their flights since July 24 because of the dispute.

Barcelona’s airport, like others in Europe, was also affected by major delays in police passport controls following new European Union regulations several weeks ago.