HARARE — A teacher pinches a crumbling stub of chalk, holding a rag for an eraser in his other hand, as groups of pupils huddle around scarce textbooks for their lessons in a poor Harare suburb.

"Things are not well," the primary school's head Islam Madosi told AFP. "The whole system is down.

"There are shortages of everything that is required for the smooth running of the school, from textbooks down to basic requirements like chalk."

Six months into Zimbabwe's unity government, this classroom on the outskirts of the capital is typical of schools in a country that once boasted one of Africa's best education systems.

Without supplies, schools are having to improvise to keep their classes running, after thousands of teachers fled due to economic hardship and the political violence of the last year.

"If you look at textbooks for example, ideally each pupil should have their own textbook or share at a ratio of one textbook for three pupils," Madosi said.

"But we have a situation where seven and in some cases 12 pupils share one book. In the worst cases, some textbooks are just not available -- or only the teacher has a personal copy.

"In the end the teacher spends most of his time doing clerical work, that is, copying exercises and writing on the board."

The crisis in Zimbabwe's state-run schools threatens the country's status as one of the most literate societies on the continent. It is one of the biggest challenges facing the six-month-old unity government.

Education Minister David Coltart told a parliamentary committee recently that the country had lost more than 20,000 teachers since 2007.

By AFP