About 22 percent of Syrian schools have been destroyed or badly damaged in over two years of unrest, jeopardizing the education of 2.5 million children, Save the Children aid agency has said.Over the past year, the Syrian crisis contributed to a dramatic rise in the number of violent incidents affecting children's education worldwide, the UK-based aid agency said in a report issued on Friday. The agency said that over 70 percent of 3,600 such incidents in 2012 took place in Syria. It added that school buildings were bombed, teachers came under violent attacks and children were recruited by armed groups. The agency stated that the violence destroyed or rendered unusable some 3,900 schools across Syria by January 2013. "But more recent estimates in April show a very rapid increase in this number, with 22 percent of the country's 22,000 schools rendered unusable," it said. "The combined effects of conflict have jeopardized the education of 2.5 million school-age children and young people." Save the Children Chief Executive Jasmine Whitbread said in a statement attached with the report, "The classroom should be a place of safety and security, not battlegrounds where children suffer the most appalling crimes. Children who are targeted in this way will be paying the price for the rest of their lives." On June 30, Syria’s Local Administration Minister Omar Al Ibrahim Ghalaounji said that more than two years of foreign-sponsored terrorism in the country has damaged about 9,000 state buildings and cost $15 billion in losses to the public sector. Ghalaounji said in comments published in Syrian newspapers that the damage worth of $15 billion to the public sector was caused between March 2011 and March 2013. He added that the damage was the result of "terrorist attacks on government buildings and infrastructure." Former Syrian Planning Minister Abdullah al-Dardari has recently said that the Syrian crisis has cost $60-$80 billion in damages to the country’s economy. He stated that the Syrian economy has contracted by about 35 percent, compared to the 6 percent annual growth the country enjoyed in the five years before 2011. According to Dardari, Syria’s economy has lost about 40 percent of its gross domestic product (GDP), and there are some 2.5 million unemployed people in the country today. Syria has been gripped by deadly unrest since 2011. According to the United Nations, more than 90,000 people have been killed and millions of others displaced in the violence. Damascus says the chaos is being orchestrated from outside the country, and there are reports that a very large number of the militants are foreign nationals. The Syrian government says the West and its regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants.