(Adds comments from SSNP news conference) By Tom Perry BEIRUT, Dec 21 (Reuters) - Lebanese police seized large quantities of explosives, detonators and timers in the homes of members of a pro-Syrian group in north Lebanon on Thursday, security sources said. Police surrounded some of the Beirut offices of the Syrian Social Nationalist Party (SSNP) -- an opposition group which responded by accusing the authorities of harassment and warned against more raids. Seven SSNP supporters or activists were arrested in the northern Koura province, including a senior member. The SSNP said most of the weapons seized dated back to the 1980s -- the height of Lebanon's 1975-1990 civil war. "The party calls for an immediate halt to raids and the pursuit of National Socialists," party leader Ali Qansou told a news conference. "The National Socialists' patience has limits." A police statement confirmed the seizure and some arrests but did not say to which group the detainees and the explosives belonged. "A force from the Internal Security Force raided these houses and found inside them a large quantity of explosives, electrical detonators and timers in addition to a large cache of weapons," the statement said. The SSNP was founded in 1932 and called for a greater Syrian state which would have included Lebanon. It is allied to the Hezbollah-led opposition, which is demanding veto power in Prime Minister Fouad Siniora's cabinet. Opposition supporters have been holding a round-the-clock protest in central Beirut since December 1 calling for Siniora to quit and pressing the opposition's demand for veto power in government. Qansou said the arrests raised "questions about whether the authorities' intention is to harass the opposition forces, which are moving in the street peacefully and democratically". Siniora's anti-Syrian government came to office after the withdrawal of Syrian troops from Lebanon last year. The withdrawal was brought about by international pressure and mass protests triggered by the assassination of former Prime Minister Rafik al-Hariri in February 2005. Many Lebanese blame Syria for the killing. Damascus denies involvement. Since then Lebanon has been shaken by 15 major explosions, assassinations and attempted assassinations aimed at anti-Syrian figures. A U.N. team is probing all those attacks. An anti-Syrian Christian cabinet minister, Pierre Gemayel, was shot dead by gunmen near Beirut last month. (Additional reporting by Leila Bassam and Nadim Ladki)
