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Amateur video purports to show shelling in Homs and gunfire that sends crowds of demonstrators scattering in Aleppo on the third day of a fragile ceasefire.

Hopes that a U.N.-brokered truce would end 13 months of bloodshed in Syria appeared to suffer a blow as opposition activists said government forces had resumed bombardment in Homs on Saturday (April 14).

An artillery attack by forces loyal to President Bashar al-Assad on the battered city of Homs would be the first since the ceasefire came into effect two days ago.

Syria's state news agency SANA and opposition groups traded blame on Saturday for gunfire in Syria's second city of Aleppo, which wounded three people, according to the Syrian Observatory for Human Rights (SOHR).

The Syrian government has repeatedly denied access to journalists, making it impossible to verify the reports independently.

The United Nations Security Council voted on Saturday to authorise advance U.N. team to monitor the fragile ceasefire which aims to end the violence

during the 13-month uprising against Assad.

The United Nations estimates that Assad's forces have killed more than 9,000 people since the uprising began. Authorities blame the violence on foreign-backed militants who they say have killed more than 2,500 soldiers and police.