Syria's al-Qaida-linked Nusra Front claimed responsibility on Twitter for the blast in Tripoli's predominantly Alawite neighbourhood of Jabal Mohsen yesterday, saying it was a twin suicide attack.
George Kitane, the head of paramedics at the Lebanese Red Cross, told the private satellite station al-Jadeed that seven people were killed and 36 wounded in the attack.
The state-run National News Agency said the attack killed nine people and wounded more than 35, citing its local reporter for the casualty figures. It said two suicide bombers carried out the attack, identifying them as Lebanese citizens from the nearby poor neighbourhood of Mankoubeen.
Tripoli has been relatively quiet recently after years of tension between its majority Sunni population and its Alawite minority. Embattled President Bashar Assad in neighbouring Syria is an Alawite and support for him in Tripoli has sparked violence there before. Most of the Sunnis in Tripoli support the predominantly Sunni Syrian rebels trying to overthrow Assad.
Lebanon's al-Qaida-linked group, the Abdullah Azzam Brigades, has claimed responsibility for some of the attacks.
It has warned that attacks will continue as long as the militant Shiite Hezbollah group takes part in Syria's civil war alongside Assad's military.