Lebanese troops found a stash of weapons, including Grad rockets and mortar shells, at the home of Syrian man in northern Lebanon Wednesday, a security source told AFP.

"Army units raided an apartment being rented by a Syrian citizens this morning in the town of Aidamoun near the Lebanese-Syrian border. They confiscated a number of weapons," the source said.

Among them were three Grad rockets, six mortar shells, explosive devices and a machine for manufacturing them, as well as a sniper's rifle and ammunition.

The owner of the apartment, its tenant and other Syrian and Lebanese citizens were arrested in connection with the discovery.

The war in neighbouring Syria has regularly spilled over into Lebanon, with rebels launching attacks from its territory and Syrian war planes and helicopters attacking Lebanese areas on the border.

Lebanon's powerful Hezbollah movement is actively fighting for the regime in Syria, and Syria's rebels have found refuge in parts of the border area inside Lebanon, running weapons and fighters across the porous border.

There are also more than 90,000 registered Syrian refugees in Lebanon, with the real number believed to be even higher.