The United Nations special envoy to Syria has told the Security Council that the country is still experiencing unacceptable levels of violence, despite an April 12 ceasefire.Kofi Annan, who was briefing the council via videolink from Sweden on Tuesday, said he was "particularly alarmed by reports that government troops entered Hama yesterday after observers departed, firing automatic weapons and killing a significant number of people”."If confirmed, this is totally unacceptable and reprehensible,” Annan, who also represents the Arab League on the Syrian crisis, said. "Two observers have been stationed in Hama today.”As violence flared in the Syrian capital of Damascus, Annan on Tuesday told the 15-nation body "we need eyes and ears on the ground, able to move freely and quickly” to watch over the ceasefire.He made clear that Syrian forces had not withdrawn heavy weapons and returned to their barracks, as they are required to under a six-point peace plan he drew up."The situation in Syria continues to be unacceptable,” Annan said. "The Syria authorities must implement their commitments in full, and a cessation of violation in all its forms must be respected by all parties.”‘Monitors brought death’Manhal, an activist in Hama, told Al Jazeera that the visit of the observers to the central city’s neighbourhood of Arbaeen on Sunday was followed by a brutal crackdown by government forces the next morning.