Four hand grenades were tossed in the Tripoli neighbourhood of Lebanon\'s Bab al-Tabbaneh region on Wednesday evening, a security source announced Thursday morning. The source said the bombs, thought to be Energa grenades, were thrown near a warehouse in Bab al-Tabbaneh, near an area that witnessed tension over the Syrian crisis. Security sources told Arabstoday in an exclusive statement that a group of men, who were hired to destabilise security in the city, threw the hand bombs from an unknown car while driving on the streets. Since the unrest in Syria erupted a year ago, tension has run high in Tripoli, where protests against President Bashar al-Assad take place on a weekly basis. In February, clashes erupted between the predominantly Alawite Tripoli neighbourhood of Jabal Mohsen and mainly Sunni district of Bab al-Tabbaneh, killing four and wounding dozens.