BERLIN (AP) - A union representing Lufthansa flight attendants has called members at Frankfurt and at Berlin's Tegel airport out on strike as it escalates a dispute with Germany's biggest airline over pay and conditions.

The UFO union called on Berlin-based members to walk out for eight hours starting at 5 a.m. (0300 GMT) Tuesday, and their counterparts at Frankfurt, Germany's busiest airport, to follow starting at 6 a.m. (0400 GMT).

UFO also plans to hit Germany's second-biggest airport, Munich, on Tuesday. An 11-hour walkout there was set to start at 1 p.m. (1100 GMT).

The union opened its strike campaign with an eight-hour walkout in Frankfurt last Friday and warned of more to come if Lufthansa didn't give ground.

Lufthansa said the walkouts would force it to cancel "a majority of flights."

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Associated Press