Security staff members at Frankfurt Airport resumed work at 11 p.m. (2200 UTC) local time on Friday, ending a 21-hour strike that had caused the international airport to temporarily suspend operations.

Delays were expected to continue into Saturday. However, it was not immediately how many airlines would be affected.

"The terminals are still full, but it's nothing compared to the situation this afternoon," a Frankfurt airport spokesperson said on Friday evening.

Strike action called by ver.di trade union led some 800 of the airport's 5,000 security staff members to halt work on Friday. The absence of personnel responsible for carrying out the necessary security checks on passengers, baggage and freight caused numerous flight cancellations and massive delays throughout the day.

FrankfurtAirporthad urged passengers to avoid the terminals because of "massive strike action."

The union protest on Friday followed four rounds of talks between ver.di and employers' association BDSW, which ended without an agreement. The next round of talks is scheduled for March 5.

kms/slk (AP, AFP, Reuters, dpa)