(Adds details on fourth victim, military saying no new curfew)
BEIRUT, Jan 26 (Reuters) - Shi'ite Muslim Hezbollah and allies held funerals on Friday for three activists shot dead during sectarian clashes in Beirut and called for unity among the Lebanese to stop their country sliding to civil war.
The Lebanese army lifted a curfew in Beirut, but schools and universities were closed a day after Sunni-Shi'ite violence killed four people and injured some 200. The Sunni Future group said the fourth victim was one of its activists.
Images of gunmen on rooftops and street fighting rekindled memories of Lebanon's 1975-1990 civil war that started as a conflict between Christians and Muslims and sucked in Palestinians, Syrians and Israelis. Around 150,000 people were killed in the conflict that left much of the country in ruins.
"We urge all religious figures, Christian and Muslim, and all sensible people in Lebanon to shoulder their responsibility before it's too late," senior Hezbollah official Sheikh Mohammed Yazbik told mourners at one of the funerals.
"This pure, precious blood was spilled for the sake of unity and it will leave its mark."
Hundreds took part in the east Lebanon funeral for the Hezbollah student shot dead during clashes between government loyalists and opposition followers of Hezbollah and its Shi'ite allies at a university in Beirut.
In the funeral of another activist in the Beirut slum of Ouzai, mourners fired salvos of automatic weapons into the air as the body was taken to his house for one last time. Women on balconies threw rice at the procession as gunfire echoed around.
"Death to Siniora, death to Jumblatt," mourners in the procession chanted, referring to Prime Minister Fouad Siniora and one his main backers, Druze leader Walid Jumbalatt.
"The lads want to respond. But the party doesn't and we follow the party," Ibrahim Nasrah, 21, said. "If they attack us, then of course there will be a reaction."
CALM BUT TENSE
Traffic remained thin in the streets of mainly Sunni districts after the army lifted the curfew at 6 a.m. (0400 GMT), but it maintained a heavy presence in tense neighbourhoods.
Military sources said there was no need for another curfew on Friday night as the security situation was under control.
"It's very bad. It's going to be like Iraq here," muttered a vegetable seller in a religiously mixed area of the capital.
"God damn whoever awakened it!" read the headline in As-Safir newspaper, referring to the sectarian violence.
Leaders from both camps called for calm but their television stations on Friday blamed each other for starting the clashes.
Hezbollah, which has a mighty guerrilla force that withstood a 34-day war with Israel last year, has vowed never to turn its guns against its Lebanese foes. It remains the only group to have officially kept its arms after the civil war.
Jeffrey Feltman, the U.S. ambassador in Beirut whose country backs Siniora against Hezbollah and its Shi'ite and Christian allies, said the situation had become "quite dangerous" and Syria was involved once again.
The opposition launched nationwide protests on Tuesday which shut down much of Lebanon and sparked violence in which three people were killed and 176 wounded that day.
The general strike intensified a street campaign that began on Dec. 1 when opposition supporters began camping out near Siniora's offices in central Beirut to back demands for veto power in government and early parliamentary elections. (Additional reporting by Tom Perry)
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