After a decade of unprecedented growth, the UN's peacekeeping efforts are overstretched with 113,000 military, police and civilians deployed in 18 missions on five continents, a top UN official said Friday. UN peacekeeping chief Alain Le Roy told the Security Council he believes 2009 will be a pivotal year with several missions facing risks so significant there is a potential they fail. Le Roy spoke at a council meeting called by Britain and France to start a wide-ranging discussion on peacekeeping challenges. Britain's U.N. Ambassador John Sawers said that the challenges of keeping and building peace have become more demanding as many conflicts now involve rebel groups and other "non-state actors."