Thousands of Pokemon Go players stormed the National Palace of Culture (NDK) on Saturday afternoon, daily newspaper Standart reports.

People from Sofia, but also neighboring countries arrived in front of NDK in Bulgaria’s capital to look for a unique Pokemon “released” right inside the capital’s landmark.

There were participants from Serbia, Macedonia, Greece, Romania and elsewhere, according to Standart.

Organizers hope that the number of participants, which is yet to be officially confirmed (with 10 000 having said they would attend) could become the biggest hunt for Pokemon so far. San Francisco’s number of last week reached 9000. A definitive number of Sofia is not expected to be known before Sunday evening.

Like elsewhere in the world, Pokemon Go has already turned into a craze in Bulgaria.

Authorities, however, are already warning against looking for Pokemon without paying enough attention to one’s surroundings.

State-owned railway company BDZ earlier this week released a statement that called on players to avoid “searching for Pokemon in railway areas” as trains cannot stop quickly enough to avoid hitting people or vehicles.