A powerful car bomb killed a front-runner to become the next head of Lebanon's army in an attack Wednesday that many feared aimed to wreck attempts to elect a new president and damage the military, which has kept the turmoil-plagued nation together.

The blast that killed Brig. Gen. Francois Hajj and his driver was a new shock in Lebanon's year-long political crisis — the first such attack on the military, which is widely seen by Lebanese as a neutral force keeping the feuding sides apart.

With no claim of responsibility, there was widespread speculation over the motive for the attack. Some anti-Syrian politicians accused Damascus, saying it was trying to torpedo efforts to elect a president, though Syria's foreign minister quickly condemned the bombing.

Others said the attack could be a warning to the military to stay out of politics or vengeance by Islamic militants for an army offensive that Hajj led against them last summer.

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The confusion highlighted how Wednesday's attack was unusual in both target and timing, coming at a time when Lebanon's feuding politicians are struggling to chose a new president. The post has been empty since Nov. 23 when Emile Lahoud's term ended.

Hajj's boss, army commander Gen. Michel Suleiman, has emerged as a possible consensus candidate for the post, though his election has been held up by continued political wrangling. Hajj, a Maronite Christian, was a leading candidate to replace Suleiman as head of the military if Suleiman becomes president.

Since 2005, Lebanon has seen a string of similar bombings and attacks that have killed eight prominent anti-Syrian figures. The perpetrators have never been identified, but anti-Syrian politicians who back Lebanon's government have accused Damascus of being behind the attacks, a claim Syria has denied.

But Lebanon's military has remained on good terms with the Syrians and has largely acted with impartiality in Lebanon's bitter political power struggle between allies and opponents of Damascus, winning it the respect of both camps. Suleiman was believed to have the tacit consent of Syria for the presidency, though Damascus has not publicly taken a stance.

Syrian Foreign Minister Walid Moallem told reporters in Damascus, "We condemn this criminal act and every measure that jeopardizes Lebanon's security and stability." An unidentified Syrian official in the state news agency SANA blamed Israel for the killing.

In Washington, State Department spokesman Sean McCormack said the bombing was "highly disturbing" given Lebanon's crisis. He said the U.S. did not know who was behind the attack but said Lebanese must be left to choose their president "free from outside interference." Washington has often accused Damascus of meddling in Lebanese politics.

McCormack praised Syria's denunciation of the bombing as "positive" — a sign of the somewhat warmer ties between the two rivals after Syria attended last month's Mideast peace conference in Annapolis. But he added that "while denunciations are useful, they need to be backed up by actions."

The White House also declined to speculate about who was to blame.

"They're still looking into it. In the past, there have been incidents where we would blame Syria, but I am not prepared to do that until that review is complete," White House press secretary Dana Perino said.

Fears have been high that the power vacuum could lead to violence between Lebanon's two camps. Wednesday's bombing prompted calls for Lebanese to rally together.

Anti-Syrian leader Walid Jumblatt called for dialogue with the opposition, which is led by Hezbollah, Syria and Iran's ally. "The nation and the army come first," Jumblatt said on television, calling for an "honorable" political solution acceptable to both feuding camps.

The blast went off at 7:10 a.m. (05:10 GMT) on a busy street with school buses and morning commuters in Baabda, a mainly Christian suburb of Beirut where the presidential palace is located and where army presence is heavy.

Hajj, who lives in the area, had left his home few minutes earlier, probably heading to his office at the nearby Defense Ministry, security officials said, speaking on condition of anonymity in accordance with military rules.

A parked car packed with 35 kilograms (77 pounds) of TNT exploded, apparently set off by remote control, ripping through Hajj's SUV, setting several other nearby ablaze and knocking a crater two meters (yards) wide and a meter (yard) deep into the pavement.

Two bodies were thrown about 15 meters (yards) by the force of the blast. Troops sealed off the area as firefighters tried to put out the flames in at least two cars.

The security officials initially said the general, his driver and bodyguard who always drove with him were killed, and that emergency workers were searching in nearby bushes for a possible fourth body. But the officials late Wednesday said body parts found in the area belonged to only two bodies, Hajj and his driver.

The military, in a statement confirming Hajj's death, refrained from placing blame, saying only a "criminal hand" was behind the attack.

Military chief Suleiman called on all sides "not to use the blood of the martyr in politics or in an attempt to cast doubt about the military's abilities."

"No matter what terrorism does it will not make the army or the Lebanese people submit," he said in a statement.

Prime Minister Fuad Saniora said the aim was to undermine the army's role. "I am confident their (attackers') goals will fail and the army's morale will remain high," he told a meeting of security chiefs Wednesday.

But some in the anti-Syrian coalition that backs Saniora's government pointed the finger at Damascus.

Telecommunications Minister Marwan Hamadeh, speaking to Associated Press Television News, accused the "Syrian-Iranian axis" of hitting the military, "the only body in Lebanon who can balance the power of Hezbollah and other militias in the country."

Hezbollah denounced the assassination, calling it "a great national loss." Christian opposition leader Michel Aoun, a former army chief who is allied with Hezbollah, was visibly shaken, telling reporters he had supported Hajj to become the new army commander if Suleiman became president.

Suspicion also fell on Islamic militants. Hajj had led a three-month military campaign that crushed al-Qaida-inspired militants in the Palestinian refugee camp of Nahr el-Bared in northern Lebanon over the summer.

Islamic militants were believed linked to a car bomb attack that killed six Spanish troops in the U.N. peacekeeping mission in southern Lebanon in June.

The failure to elect a president since September has embroiled Lebanon in its worst political crisis since the end of the 1975-90 civil war.

Supporters of Saniora and the opposition are locked in a dispute over how to elect Suleiman to the post. Suleiman's election requires a constitutional amendment because currently a sitting army commander is barred from the post. Parliament was to make another try on Monday.

A funeral for Hajj will be held Friday in the Christian heartland and he will be buried at his hometown in southern Lebanon near the Israeli border.