Violence isn't free speech, U.N. says Palestinians burn American and Israeli flags during a demonstration against a controversial film mocking Islam, in Gaza City, on September 14, 2012. 19 (UPI) -- Violent demonstrations are inexcusable and those responsible must face prosecution, a U.N. envoy on freedom of assembly said from Geneva. A wave of unrest spread across much of the world in response to a low-budget film produced in the United States that was viewed as insulting to Islam. Scores of people have been injured or killed during recent anti-American demonstrations. Maina Kiai, U.N. special envoy on the rights to freedom of assembly, said the freedom to protest is not an excuse to commit violence. "It is the duty of states to distinguish between peaceful and non-peaceful protesters," he said in a statement. The latter must be prosecuted and brought before an independent court that guarantees the right to due process. U.S. embassies or consulates in Pakistan, Libya and Albania issued warnings that some diplomatic services were suspended because of protests in the respective countries. German and British embassies in Sudan were attacked last week and the French government issued a warning to its embassies in response to the publication of a cartoon viewed as denigrating to the Islamic Prophet Muhammad.