Four people were killed and 10 others wounded on Tuesday when two mortar shells slammed the municipal building in Syria's northern city of Aleppo, the state- run SANA news agency reported. While not spelling details about the Aleppo attack, SANA said that nine other people were injured in another mortar attacks in the capital Damascus. One of the Damascus' mortars landed near the Red Crescent hospital at Baghdad Street and injured six people, SANA said, adding that the wounded people were transported to nearby hospitals. Another mortar landed behind a school at al-Abbasiyen area and wounded three, SANA said. The attacks are the latest in a series of endless mortar shelling by the rebels on several districts of Damascus, as part of their reprisal against the government troops' imposed siege on rebel-held areas and their advancement on several fronts nationwide.