Teachers hit out Friday at Greece's closure of secondary schools from next week, as the country enters a second nationwide lockdown aiming to curb the aggressive spread of coronavirus.
The World Health Organization has cautioned that closing schools should be seen as a last resort, saying there is no clear evidence they are "a main driver of the transmission."
And while many European countries are locking down to try and control an explosion in cases, they are attempting to keep schools open unlike during a first lockdown in the spring.
"We cannot afford a Covid-19 lost generation," WHO's regional director for Europe Hans Kluge told AFP.
In his announcement of a new lockdown on Thursday, Greek Prime Minister Kyriakos Mitsotakis nevertheless said secondary school students would have to do distance-learning once again.
But he promised that kindergartens and primary schools would remain open -- for now.
Theodoros Tsouchlos, president of the secondary school teachers' union, said he feared the schools would eventually have to remain closed much longer.
"Distance-learning cannot replace the physical presence of students in the classroom," he told AFP.
"We warned the education ministry to prepare for this situation.
"We had requested small classes of 15 students, more hirings of teachers and cleaners at schools" to avoid their closure.
Tsouchlos said many high school students had already fallen behind in their studies during the first wave of the pandemic.
The second lockdown could raise inequalities further, as some students don't have access to wifi or own a laptop, or else it is used by parents for teleworking, he added.
"These are issues that the government should have prepared for during the summer, but instead it acted as if everything was under control," Tsouchlos said.
"This is the second wave and we don't know how many will follow."
Thanasis Kikinis, head of the association of Greek primary school teachers, added that "judging by the progress of the virus, I'm almost certain that primary schools will also close soon."
Up until now, "the schools have been operating without ensuring adequate health conditions in classes with too many children."
More than 700 students across the country tested positive to the coronavirus in just one week.
In the meantime, a high school teacher was given a 12-month suspended jail term after being arrested on October 23 for not wearing a face mask in class.