Middle school students in Poland are taking important middle school exams even though a nationwide teachers' strike entered its third day, forcing exam authorities to ask help from retired teachers, religion tutors and those not on strike.

It was not clear early Wednesday whether the exams could be held in all middle schools, given the shortage of staff over the strike on pay.

Last-ditch talks between the government and teachers' unions to end the standoff that has closed thousands of Poland's schools collapsed on Tuesday.

The head of Poland's national exam commission, Marcin Smolik, said he could not guarantee that exams would be held in every one of some 7,000 middle schools.