The video posted on Youtube on Thursday shows a UN monitor crawling to escape heavy gunfire in Khan Sheikhoun, north of Hama.
UN observers came under attack on Tuesday when a shell hit one of their vehicles during a visit in Khan Sheikhoun.
According to activists, UN monitors were observing a rally for the funeral of a man killed on Monday when Syrian forces opened fire. The activists says the size of the crowd prompted security forces to open fire. He also added that 4 people were killed and dozens were injured.