ATHENS, Greece — Three people have been arrested in northern Greece on suspicion of systematically counterfeiting works by leading Greek artists and selling them as originals through an online auction house, police said Friday.

A police statement said the arrests were carried out Wednesday on the eve of a live internet sale of 123 paintings and sculptures by the auctioneers, who were based in the northern city of Thessaloniki.

An art expert from Greece’s National Gallery who examined the works found that all 123 were “clearly” forgeries, the police statement said.

Officers raided the auction house premises and four locations where paintings were allegedly forged, and seized more than 800 other artworks whose authenticity and provenance are under investigation.

Based on the sale estimates, authorities said Thursday’s planned auction was expected to have raised between 288,000 and 398,000 euros ($305,000 and 421,000).

The artworks to be sold included paintings by deceased 20th-century artists Yannis Gaitis, Nikos Hadjikyriakos-Ghikas and Alekos Fassianos, according to the auction catalogue. Their work is highly popular among collectors and can command prices that run into five figures.

The three suspects, two men aged 70 and 62 and a 42-year-old woman, were charged Friday with repeated acts of forgery, as well as receiving and trying to sell products of crime.