CREDIT: Supporters of the anti-Syrian coalition wave Lebanese flags during a rally to mark the third anniversary of the killing of former Prime Minister Rafik al-Hariri, in Beirut February 14, 2008. REUTERS/Sharif Karim

BEIRUT (Reuters) - Lebanese soldiers deployed in several mixed Sunni-Shi'ite streets of Beirut on Saturday and ended sectarian riots that left at least 14 people injured and several cars and shops smashed.

Security sources said followers of Sunni Muslim Saad al-Hariri's Future Trend movement battled supporters of the Shi'ite Hezbollah and Amal groups with sticks, knives and stones in Ras al-Nabei, Mazraa and Barboor areas of Beirut.

It was not clear what sparked the night-time clashes but tension has been simmering for weeks. Smaller incidents have been reported almost on daily basis.

Hariri's anti-Syrian ruling coalition is locked in a 15-month-old power struggle against an opposition led by Hezbollah, which is backed by Syria and Iran.

The political crisis has left Lebanon without a president since November. It has spilled into deadly street clashes on several occasions over the past year. Last month seven Shi'ite protesters were shot dead, mainly by Lebanese troops.

On Saturday, scores of Lebanese soldiers fired into the air to disperse rioters from both sides. At least 14 people, many with broken bones or cuts, were injured in the fights.

Some media reported both sides exchanged fire in some places but security sources said most of the shooting was by troops and into the air.

(Writing by Nadim Ladki; Editing by Matthew Tostevin)