German police have arrested two teenagers on suspicion of planning a terror attack in the country, security sources cited by German media said Wednesday.

The boys, aged 15 and 16, had allegedly discussed plans to attack "infidels" and had identified a synagogue and a Christmas market as potential targets, according to the German news agency dpa. It wasn't immediately clear how serious the alleged plot was.

Prosecutors said the 15-year-old suspect was detained in the western state of North Rhine-Westphalia following a search at his home. A court ordered he be kept in custody pending a possible indictment.

The 16-year-old was detained in the eastern state of Brandenburg.

According to sources cited by dpa, the authorities took action and detained the teens as a precaution after the 15-year-old named a specific date and public place.

Public broadcaster ARD reported that the young man had called for a "holy war" against the West and announced an attack on December 1 in a video on social media platform Telegram.

Earlier Wednesday, Germany's domestic intelligence agency said the terror threat in the country had increased following the Hamas attack on southern Israel on October 7.

nm/lo (AP, dpa)