Palestinian President Mahmoud Abbas pledged on Saturday to improve conditions for teachers whose three-week-old strike has closed several schools in the Israeli-occupied West Bank. In a previously unscheduled television address Abbas, flanked by Prime Minister Rami Hamdallah, promised a 10 percent pay rise, a management review and the implementation of a 2013 work agreement. The average monthly salary for a teacher is $600. A school head with a master's degree and 25 years of service can earn $700. Abbas's West Bank-based Palestinian Authority (PA) has been pleading with teachers to return to class, warning that pupils otherwise risk a "lost year." Most of the promises given by Abbas on Saturday are only to take effect from September 2017 but he asked them to go back to work this Sunday, the first day of the Palestinian working week. The PA, which spends nearly half of its budget on wages for its 180,000 civil servants, has been in chronic economic crisis for years. The monthly wage bill of nearly $150 million is 16 percent of Gross Domestic Product, one of the highest in the world. The PA was supposed to have been an interim body and be replaced in 1999 by a sovereign state of Palestine but a peace treaty with Israel has proved elusive and foreign aid to the administration has halved over the past five years. Of the 45,000 teachers in Palestinian schools, nearly 36,000 are in the West Bank. In the Hamas-ruled Gaza Strip, where close to 75 percent of residents are refugees, the United Nations runs most schools.