About 5,000 people gathered in the northern Greek city of Thessaloniki on Sunday to protest against a new type of identity card to be introduced later this month, police said.

Carrying Greek flags and banners, the protesters rallied at the city's iconic White Tower, a waterfront former fortification, chanting slogans and the national anthem. They played a speech by the late former head of the Greek Orthodox Church, Archbishop Christodoulos of Athens, who had warned about what he called the enemies of the Greek people.

Later, they marched through the city center before dispersing without incident.

The machine-readable cards will replace the type of ID currently issued and will contain the same information, such as name, parents' name, address and height. The only extra information, blood type, is optional.

But the cards have inspired conspiracy theories and some people assert the new IDs contain chips that will allow authorities to pinpoint cardholders' location or even control their minds. The majority of the ID cards' opponents are deeply religious.

An exasperated Prime Minister Kyriakos Mitsotakis said in a recent cabinet meeting that the IDs will not contain "any chips or cameras or listening devices.”

The protesters' religious connections poses a problem for the Church of Greece, some of whose bishops encourage the protests. Archbishop Ieronymos of Athens, who has none of the fiery rhetoric of his predecessor, Christodoulos, has said the Church's Holy Synod will issue a statement about the IDs in a few days and has counseled "judiciousness and prudence.”

A protest rally will take place in the capital Athens next weekend.

The new IDs, which conform to an EU-wide standard, will become obligatory by August 2026.