* Army says 20 rockets from Syria hit Lebanon on Friday
* Rockets strike both pro- and anti-Syrian opposition towns (Adds Lebanese army statement, paragraph 2)
By Rami Bleibel
HERMEL, Lebanon, Jan 17 (Reuters) - Rocket fire into the Lebanese border town of Arsal killed at least seven people and wounded 15 on Friday, Lebanon's state news agency said, in one of several such salvoes to hit towns bordering war-torn Syria.
At least 20 rockets launched from across the border struck Lebanese frontier areas, according to the Lebanese army, in further spillover from Syria's civil war that has raised tensions across Lebanon.
Lebanon, itself shattered by civil war from 1975 to 1990, has been struggling to keep itself out of the nearly three-year conflict raging in its much larger neighbour, with more than 100,000 people killed there.
But with sectarian sympathies aligning different Lebanese groups with Syria's warring parties, spillover has become increasingly frequent. Lebanon is now coping with increased car bombings, some of them hitting the heart of the capital Beirut.
The National News Agency said a single rocket was responsible for the death toll in Arsal, an area sympathetic to the mostly Sunni Muslim rebels fighting to topple Syrian President Bashar al-Assad.
A Lebanese national security source said there were eight casualties from two rockets in Arsal, but could not confirm how many were dead or wounded. Security sources inside the town said seven rockets crashed around Arsal, with a field clinic and a Syrian refugee camp both hit.
The security source said that a Syrian fighter jet was targeting a town on the Syrian side of the frontier, but was not the source of the rocket fire.
Rockets also crashed into areas around the northern Lebanese border town of Hermel. One hit inside Hermel but caused no major damage, while two more rockets fell in neighbouring villages, without reported casualties.
Hermel is supportive of Lebanon's powerful Shi'ite Muslim militant movement Hezbollah, which has been fighting in Syria on the side of Assad, himself from the minority Alawite sect, an offshoot of Shi'ite Islam.
A day earlier, Hermel, which is regularly the target of rocket and mortar attacks from Syrian rebels, suffered its first car bomb attack.
The attack, which killed four people including a suicide bomber inside the car, was claimed by the Lebanese branch of the Nusra Front, the Syrian rebel group affiliated with al Qaeda. It has not been possible to verify the claim. (Writing by Erika Solomon; Editing by Mark Heinrich)