Public sector teachers in the poor West African nation of Guinea marked the first day of the new academic year on Wednesday by launching an "unlimited" strike to demand salary increases.The strike by the powerful SLECG teachers' union followed failed negotiations with the government."There aren't any teachers, which is not good for the country or for education, or for humanity itself," the principal of one of Conakry's largest high schools told AFP."We can't just open the schools... but picking up the teachers and students from their homes isn't our responsibility," he said.An AFP reporter who went to around 10 elementary, middle and high schools did not meet any teachers or pupils.The strike was followed in northern Labe, western Boke, central Mamou and Faranah, as well as N'Zerekore in the south.The SLECG also went on strike for a month earlier this year, ending on March 19 after they gained a guarantee of a pay hike agreed in 2017.But now they charge that the agreement has not been fully honoured."The fight for teachers' well-being has only just begun," said union leader Aboubacar Soumah.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.