Slovak teachers on Tuesday started a series of demonstrations to demand a higher-than-proposed increase in their salaries.
Tuesday's public rallies in Zilina of central Slovakia and Presov of east Slovakia were attended by hundreds of teachers.
The education trade union has demanded a pay rise of at least 10 percent. The teachers argued that compared with other members of the Organization for Economic Co-operation and Development (OECD), Slovakia does not allot enough money to education.
But the Slovak government said due to the shortage of money, it would only fulfill a part of teachers' demands. It has decided to increase the teachers' salaries by 5 percent next year.
"We do not want to escalate social tension, but we are not ready to stop the effort joined en masse by the education staff and lately also students unless we get the required guarantees," the trade unions' statement said.
The protest will culminate in Bratislava and Kosice of eastern Slovakia on Friday.