ATHENS — Judicial authorities in Greece received instructions Tuesday to pursue the prosecution of anti-mask activists with fast-tracked trials and penalties for convictions of up to a year in prison. 

The instructions issued by a Supreme Court prosecutor described activists who oppose government orders to wear masks to curb the coronavirus as a threat to public health and public order.

While Greece's COVID-19 infection rate remains lower than in most other European Union member nations, the country has seen a sharp increase in confirmed cases since early August. The total number of confirmed cases approached 16,000 as of Tuesday.

Anti-mask groups have recently stepped up activity online and staged small street protests. Since schools reopened last week, they have focused their criticism on the requirement for students to wear masks in class.

Supreme Court prosecutor Vassilis Pliotas said the actions of anti-mask campaigners had caused "understandable concern among law-abiding citizens." He described the groups as "minor but persistent." 

Pliotas said online posts and other actions merit prosecution for the crime of agitating to break the law, an offense that normally results in a fine and has rarely led to imprisonment. 

Health authorities announced 346 new confirmed infections Tuesday — mostly in the greater Athens area, where stronger restrictions were imposed Monday — and another eight deaths, which brought Greece's overall death toll in the pandemic to 352. Anti-mask groups argue that medical advice on the effectiveness of masks has been inconsistent and that public health measures introduced by the government are broadly undemocratic. 

The government says it is relying on the advice of leading Greek and international experts and that lawmakers approved its framework of virus-related restrictions.