Police say they have arrested at least four people and seized a large amount of explosives from homes in Lebanon.
Those held are said to be part of a bloc calling for a new government
Those detained were not named by police but security sources said they were members of a pro-Syrian Lebanese party, the Syrian Social Nationalist Party.
There was no immediate comment by party officials on the arrests, which took place in the northern Koura province.
The party is part of a Syrian-backed opposition bloc which has been calling for the resignation of the government.
The bloc, led by the militant Shia movement Hezbollah, is demanding a bigger share in a new cabinet that would give it the power of veto - and has been backed by huge public protests.
A police statement said the prosecutor general had ordered the raids on several homes after receiving intelligence about explosives hidden there.
Officers also found timers, electrical detonators and a large cache of weapons, the statement said.