By: Mark Leon Goldberg on May 15, 2012 This recently uploaded video from YouTube shows an attack against a convoy of four clearly marked UN cars belonging to the small monitoring mission. No one was killed in the blast. From CNN A four-vehicle U.N. convoy was struck by an improvised explosive device Tuesday in Syria, the United Nations said. No U.N. personnel were injured, but three vehicles were damaged, said Ahmad Fawzi, spokesman for Kofi Annan, special envoy to Syria for both the United Nations and the Arab League. A video posted on YouTube shows what appears to be the U.N. observers’ vehicles in the midst of chaos in Khan Cheikhoun, part of Idlib province. A loud bang, which could be a gunshot, is heard as the cars edge forward. This is not the first attack against the observer mission. Last week, a convoy that included UN monitors suffered a bombing attack. Again, no observers were killed in the strike. However, if and when one of these attacks against the observer mission is successful and inflicts casualties or fatalities, the mission may come under serious re-consideration. Once the observer mission lacks a certain freedom of movement because of ongoing security threat, it simply will not be able to do its job. At that point, we would be back to square one. Attacks like this one today are very, very disturbing. They may portend a failure of the mission and Syria’s rapid descent into full scale civil war. UPDATE: This NYT report fills in some crucial details of this incident. In all, some 20 people were killed in the melee. Eyewitnesses reached via Skype in Khan Sheikhoun, the town where the confrontation took place in the embattled northwestern province of Idlib, said that a large crowd had turned out for the funeral of a man killed by government forces two days earlier near Hama. The mourners were surprised when a United Nations convoy rolled into town and headed toward the area where government forces are concentrated in the town, which residents refer to as the “Mantiqa,” the Arabic word for area. The observers were apparently going to survey the fortified checkpoints — the truce negotiated by Mr. Annan requires that armed forces and heavy weapons should be withdrawn from population centers. Emboldened by the presence of the monitors, some residents started demonstrating nearer to the checkpoints and the government area than they normally would. When they were at close range, the soldiers opened fire, said the eyewitnesses, and somewhere in the fracas the distinctive white United Nations vehicles were heavily damaged. An amateur video posted online shows the lead vehicle lurching and then listing, its front hood blown open, after a loud bang sends up a cloud of dust.