At least 27 people were killed in several parts of Syria on Wednesday, according to opposition activists and state media, in near-daily violations of the fractured April 12 ceasefire, DPA reported.
"At least 15 people were killed and 70 wounded when a rocket fell on a neighbourhood in (central province of) Hama," reported the Local Coordination Committees, which documents violence in the country.
The state-run SANA news agency reported that "an armed terrorist group" attacked an ambulance of the Syrian Arab Red Crescent in the Damascus suburb of Douma, killing one volunteer and wounding another.
Earlier Wednesday, opposition activists said 10 people died in shelling in Douma, the other suburb of Harasta and the northern province of Idlib near the Turkish border.
Hama and suburban Damascus were shelled after United Nations monitors visited the areas in the past two days, according to activist Haytham al-Abdallah, who said the attacks had intensified.
The opposition claimed that government forces arrested suspected activists in and around Damascus, raising fears that the regime was intimidating and possibly torturing residents who met the UN observers.
UN-Arab League envoy Kofi Annan, who brokered a peace plan between the government and the opposition, told the UN Security Council Tuesday that the government had not withdrawn troops from residential areas - a violation of the truce terms.
SANA reported earlier Wednesday that government troops had foiled an infiltration attempt by opposition rebels based in Turkey, killing one gunman.
Syria has blamed the revolt against President Bashar al-Assad's regime, which started with peaceful protests 13 months ago, on "terrorists" backed by foreign powers.
According to UN estimates, 9,000 people have died since the unrest began in March 2011.
Annan's spokesman on Tuesday cited reports from Syria as saying that people who met UN observers were either intimidated or executed by government forces.
The UN Security Council last week passed a resolution to increase the number of observers to 300. Only 10 monitors are currently in the country.