A sharp rise in the number of deaths in the Syrian uprising is casting fresh doubt on the success of a UN peace plan, and testing a ceasefire deal, BBC reports. Activists said nearly 70 people were killed on Monday, most in a government crackdown in the city of Hama. The US said the UN monitoring mission was “risky and dangerous”.The UN is pressing to increase its monitors from a handful to 300 and chief envoy Kofi Annan is due to brief the Security Council again on Tuesday.A UN-brokered ceasefire came into effect on 12 April, but although the overall level of violence has dropped since then, President Bashar al-Assad’s government has been accused of failing to abide by key terms of the truce plan, including pulling all forces from urban areas and allowing peaceful demonstrations. Activists have pointed to the situation in Hama as an example of the dangers of the UN mission. UN Secretary-General Ban Ki-moon played down fears that prospects for a successful compliance look slim, euronews.com informs. “The United Nations members have been speaking in a united voice authorising the deployment of a 300 member supervision mission in Syria.” Syrian troops reportedly fired shells and automatic weapons in the northern Arbaeen and Mashaa al-Arbaeen districts on Monday. Some 40 people were said to have died.The government’s brief account said only that security forces “pursued armed terrorist groups” which had been attacking and killing citizens in the area.The Syrian Observatory for Human Rights said rebels had earlier targeted the car of an army officer in the city, killing him and an assistant. And on Tuesday it reported that three intelligence officers were killed in Damascus.Syrian TV also reported a car bomb had exploded in the centre of the capital on Tuesday, injuring three people.