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A bomb blast set off huge fires in a mainly Christian Beirut (search) suburb Saturday, injuring five people in the third such attack in eight days. Opposition leaders blamed Syria, saying Damascus hoped to sow fear as it withdraws troops from Lebanon.

The latest attack, targeting an industrial estate in Beirut's northeastern Bouchrieh (search) area, raised tensions another notch in Lebanon, which has been gripped by political turmoil since the Feb. 14 assassination of former premier Rafik Hariri. Opposition groups have blamed longtime mentor Syria and pro-Damascus Lebanese authorities for his killing. Both vehemently deny such claims.

Opposition leaders have predicted Syrian-allied security forces would launch attacks aimed at proving Lebanon (search) was unable to control security in its own country in the midst of a Syrian troop withdrawal that continued Saturday, a demand of the United States, United Nations and Lebanese opposed to Damascus' control over this country.

"They [Syrians] promised Hariri ... that if they left Lebanon, they would destroy Lebanon," exiled Christian opposition leader Michel Aoun told Al-Arabiya TV. "And now they are doing it. They think they can destroy Lebanese national unity this way. But the Lebanese will remain steadfast till infinity."

Aoun said the situation calls for "changing the security organizations related to Syria. This can't be delayed."

A 55-pound bomb was placed between a car and a wood factory in the Bouchrieh industrial estate, Lebanon's police chief, Maj. Gen. Sarkis Tadros, quoted an explosives expert as saying. The blast left a 3-foot-by-10-foot-wide crater, destroyed nearby cars and shattered windows throughout the estate.

A Lebanese woman and two Indian workers were injured, as were two civil defense workers working on extinguishing the raging fire that engulfed at least six buildings, security officials said.

"They must love us — we got it twice in a week," Bouchrieh mayor Antoine Gebara told leading Lebanese TV station, LBC. He was referring to last Saturday's explosion in the nearby predominantly Christian neighborhood of Jdeideh that injured nine people. Five days later, another bomb blast killed three people near the port city of Jounieh, Lebanon's Christian heartland.

Witnesses said the blast on the eve of the Easter holiday occurred three hours before Catholics were to head to a midnight Mass.

The motive behind the latest attacks weren't immediately clear, but Lebanese opposition leaders have blamed Syrian security agents and pro-Damascus Lebanese authorities for trying to show a need for Syria's military presence in Lebanon.

Syrian soldiers have been based in Lebanon since 1976, a year after Lebanon's 15-year civil war started. The Syrians arrived ostensibly to provide a stabilizing force in the war-torn country, but following the end of hostilities remained and became its pseudo rulers, controlling all important political and security issues in Lebanon.

Calls for an end to Syrian interference in Lebanon reached fever pitch following Hariri's killing with Lebanese staging mass protests and the United States and United Nations demanding Damascus withdraw its forces in line with U.N. Security Council Resolution 1559 passed in September.

About 1,000 of the 10,000 Syrian soldiers remaining in eastern Lebanon's Bekaa Valley had started heading home in recent days, a Lebanese military official said Saturday. The redeployments follow the return to Syria of 4,000 soldiers in the first phase of the troop withdrawal that was completed March 17.

Lebanon's pro-Syrian defense minister, Abdul-Rahim Murad, warned that the Lebanese army may not be able to handle security if Syrian forces leave the eastern Bekaa Valley, a strategically important region for Syria's own security, particularly in facing arch foe Israel.

The Bekaa, which comprises 45 percent of Lebanese territory, "needs a lot of military forces," Murad told reporters Friday, hinting that Syrian troops may still be needed to stay in Lebanon.

Murad, who hails from the Bekaa, said the U.S. ambassador asked Lebanon's army commander recently about Lebanese army readiness to replace Syrian forces in eastern Lebanon. Murad said the commander replied that "the conditions of the military establishment do not permit this new role in the Bekaa because numerically the army is not enough."

Lebanese opposition leader Walid Jumblatt rejected Murad's comments and renewed calls on Lebanese security chiefs to resign in the face of criticism leveled against Syria and its allied Lebanese government by a U.N. fact-finding mission in a report released this week into Hariri's killing.

The report also recommended an international investigation into Hariri's murder, but added such a probe would be difficult while Lebanon's security chiefs are in place.

"It is not possible to carry out a just, clear and transparent investigation if the heads of [security] agencies remained in place," Jumblatt added Saturday. Legislator Bahiya Hariri, the slain leader's sister, also demanded the resignations.

Jumblatt was among several opposition leaders who blamed Syria for Saturday's bomb blast in Bouchrieh, the third bombing since March 19. Each attack has targeted Christian, anti-Syrian strongholds, raising fears of the return of the sectarian violence that plagued Lebanon during the 1975-90 civil war.

Jumblatt said he expected more car bombs in the coming days and in the run-up to parliamentary elections scheduled to be held by May.

Another opposition leader, Butros Harb, said the explosions were "a political message from the authorities and those behind them" to terrorize Lebanese demanding freedom and sovereignty.

The pro-Syrian camp, however, accused opposition forces of seeking the instability to invite international intervention in Lebanon.

"I think what is going on is an attempt to internationalize the Lebanese situation to allow for sending troops to Lebanon," said Karim Pakradouni, leader of the pro-government Christian Phalange party, adding he did not believe security agencies were to blame.