Syrian state media say new rebel shelling of government-held parts of the northern city of Aleppo has killed at least seven people and wounded 35.

Syrian TV says the shells hit several neighborhoods during morning rush hour in contested Aleppo, which has been the center of violence in recent weeks.

Tuesday's attack comes as diplomatic focus moves to Moscow where the U.N. envoy for Syria is arriving for talks on restoring a piecemeal cease-fire that would also include Aleppo, Syria's largest city and once commercial center.

The activist Britain-based Syrian Observatory for Human Rights confirmed the shelling, saying there are casualties.

The Observatory says more than 250 civilians have been killed in 12 days of violence in both government- and rebel-held parts of the city.