Honduran President Porfirio Lobo on Sunday threatened to fire teachers if they continue a three-week-old strike that has aggravated divisions caused by a 2009 coup.
Teachers who fail to show up in classrooms Monday will be suspended without pay, according to the president's decree, which was read on radio and television stations. If teachers don't appear by April 4, they will be fired.
Lobo said he has the power to dissolve the teachers' unions for backing the strike.
The protesters oppose a proposed law that would give parents oversight of schools and they say the government owes six months of back pay to 6,000 teachers. They also demanding the return of leftist former President Manuel Zelaya, who was ousted in a 2009 coup backed by the nation's congress and courts.
Zelaya's term ended in January 2010, but many Zelaya backers argue Lobo's election was illegitimate because it occurred under an interim government installed by the coup.
A judge last week dropped arrest warrants against Zelaya so that he can return without fear of arrest, but the former leader, an ally of Venezuelan President Hugo Chavez, said he fears he will be killed if he comes back.
The unions immediately rejected Lobo's ultimatum.
"We are in the streets and we will stay there," said Jaime Rodriguez, president of the middle-school teachers' union.
Another union leader, Daniel Duron, warned that Lobo's order "will create greater confrontation" and complicate efforts to solve the dispute through dialogue.
A union for more than 14.000 hospital workers has vowed to join the strike on Monday and a coalition of Zelaya backers, the People's National Resistance Front, is calling for a general strike on Wednesday. The teachers have been a key force within the Front.
(This version CORRECTS that arrest warrants, not charges dropped.)