Teachers from across Poland have gathered in Warsaw to demand higher wages in a long-running dispute that is emerging as another fissure in a deeply divided society.

Tuesday's protest in front of the Education Ministry comes on the 16th day of a strike that has closed most Polish schools.

Many carried signs of a black exclamation point to signal the urgency of the cause.

Poland has long ranked high in international education rankings, but teachers say current conditions are lowering standards. Many are furious that an overhaul by the conservative government has added to their work load while wages remain low.

The government and church leaders say it's wrong of teachers to force school closures in a period of final exams.