Thousands of anti-vaccine demonstrators have protested in Greece's two largest cities against plans to make coronavirus vaccines available to children 15 and older.
The protests took place outside parliament in central Athens and in the northern city of Thessaloniki.
Greek authorities have blamed a recent increase in confirmed virus cases on crowded entertainment venues.
Under new restrictions, leisure facilities will only be open to people who are vaccinated.
A mandatory vaccination policy is planned for workers at care facilities and hospitals.
In Athens, more than 5000 protesters chanted "Hands off our kids" and held up a banner reading "We say no to vaccine poison".
About half of Greece's population has received at least one vaccine dose.
"Every person has the right to choose. We're choosing that the government does not choose for us," said Faidon Vovolis, a cardiologist who has questioned the scientific research around face masks and the vaccine and heads the Free Again movement which called the protest.
Vovolis said he started the group in response to the government's "tough measures" to contain the virus.
Starting on Thursday, people as young as 15 will be allowed to book a vaccination appointment with parental consent.