BEIRUT -- At least 17 people were wounded as armed clashes renewed suddenly Sunday in Lebanon's northern port city of Tripoli after several days of relative calm, a local security source said.

Fighting broke out in the evening between the rival neighborhoods of Alawite Jabal Mohsen and Sunni al-Amerkan and al- Baqqar before escalating and spreading to Bab al-Tabbaneh, Baal al- Darawish, Syria Street, al-Omari Street, Souk al-Qameh and Hariri Project, according to the source.

Sounds of machinegun fire and explosions are echoing in the area, the source said, adding that the army was shooting back at the sources of gunfire in Bab al-Tabbaneh and Jabal Mohsen.

Late in May, at least 31 people were killed and more than 240 wounded in a week-long gun battles.

Sectarian fighting between the two main neighborhoods of Bab al- Tabbaneh and Jabal Mohsen dates back four decades to Lebanon's civil war. It has become more frequent and increasingly lethal since the start of the Syrian conflict in 2011.