Visitors go for a walk near The Gloriette in the park of Schoenbrunn Palace in Vienna, Austria on December 3, 2023, after snowfall. (PHOTO / AFP)

VIENNA - Three people were arrested in Austria on Sunday for suspected involvement in a "cross-border Islamist network" as police in the capital of Vienna stepped up controls to ensure Christmas security, local authorities said.

The Vienna public prosecutor's office said that the suspects "discussed attack plans in Vienna, Cologne and Madrid" but "there was no immediate threat of an attack in Vienna," Austrian broadcaster ORF reported.

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Austrian police have intensified checks and patrols, especially around churches, religious events and Christmas markets in the capital, citing heightened security concerns amid calls for terrorist attacks on Christian events across Europe.