U.S. pressure mounts on Syria...

[bilal]

CNN) -- U.S. pressure is mounting on Syria in the wake of the deadly bomb blast in Lebanon that killed former Lebanese Prime Minister Rafik Hariri.

A war of words is developing between Washington and Damascus, with the U.S. recalling its ambassador to Syria, and Syria shrugging off criticism of its troop presence in Lebanon and U.S. claims that it supports terrorism.

U.S. Secretary of State Condoleezza Rice said Tuesday Syria was "unfortunately on a path right now where relations are not improving, but are worsening".

Rice did not blame Syria for Monday's bomb attack that killed Hariri and 16 others, but she did challenge Syria's longstanding claim that its troops were needed in Lebanon to provide security.

"There is no doubt that the conditions created by Syria's presence there have created a destabilized situation in Lebanon," she said.

Syria's Ambassador to the U.S., Imad Moustapha, was quick to return the verbal blows.

"If anyone is trying to politically score some points against Syria, I would say ... this would be shameful," he told CNN.

"It should be very clear to everyone that if anybody is insinuating about a Syrian role in the criminal atrocity that happened in Beirut, I think they are lacking logic," he said.

In a thinly-veiled jab at Washington, he said accusations that Syria is supporting terrorism are akin to the claims, later disproved, that Iraq possessed weapons of mass destruction in the lead-up to the war.

"Syria does not support terrorism. We have said this time and again," he said.

When asked about possible additional sanctions on Syria, Rice said, "we will continue to consider what other options are at our disposal".

Meanwhile, U.S. State Department spokesman Richard Boucher said the United States has "made it clear" it wants Syria, which maintains some 16,000 troops in Lebanon, to use its influence to prevent attacks such as Monday's massive bombing.

"I have been very careful to say we really don't know who committed this murder at this point, but we do know what effect the Syrian presence in Lebanon has," Boucher said.

"And we do know that it doesn't bring security for Lebanese."

Ambassador Margaret Scobey was returning to Washington for "urgent consultations," Boucher said, because of "deep concern, as well as our profound outrage, over this heinous act of terrorism."

"Syria maintains a sizable presence of military and intelligence officials in Lebanon in contravention of the U.N. Security Council Resolution 1559," Boucher said.

In addition to Syria's troops in Lebanon, Boucher said the United States has concerns about "the continued presence and operational activities of international terrorist groups, and of the Iranian regime on and through Syrian territory, and the use of Syrian territory by the Iraqi insurgency."

Monday's bombing occurred amid increasing political tensions in advance of Lebanon's parliamentary elections in May.

Lebanon's pro-Syrian government, which counts on its neighbor for security, has come under fire from a growing anti-Syrian opposition that says Lebanon can take care of its own security.

Hariri's supporters in the Lebanese political opposition said they held Syria and the pro-Damascus Lebanese government responsible for his murder.

In Syria, government spokeswoman Buthaina Shaaban said Monday that Syrian-Lebanese relations had nothing to do with the bombing.

"We want a full investigation to show who is behind this assassination," Shaaban said.

Lebanese Information Minister Elie Ferzli rejected allegations that either the government or Syria was behind the killing. "We consider these accusations irresponsible," he told CNN.

"We consider that the assassination of Hariri is against stability. And we consider that stability is our concern. So, this action is against us," he said. "We are going to miss Hariri."

Two key members of the U.S. Senate expressed support for the ambassador's recall.

"I think perhaps tightening the screws somewhat more would be appropriate," said Sen. Kay Bailey Hutchison, R-Texas. "Everything indicates that Syria is harboring terrorists."

Sen. Byron Dorgan said the move sends a strong message. "I think it's a very serious step and will be an understandable signal to the Syrians," said Dorgan, D-North Dakota. "The Syrians have been identified as a country that's engaged in state-sponsored terrorism."

Search for attackers
Police have questioned four people and are searching for a man who claimed responsibility for the attack, which wounded 137 people.

Investigators were sifting the site for clues to the cause of the bombing that ripped through Beirut's seafront boulevard leaving rubble, burning vehicles, twisted metal and glass strewn for blocks.

Hariri's family on Tuesday rejected a government call for a state funeral, instead saying the burial set for Wednesday would be accompanied by "a popular remembrance."

Investigators said they did not yet know if the explosives were packed into a vehicle or underground, if they were delivered by a suicide bomber or some other method.

Prior to the blast, construction work was taking place at the site of the explosion.

According to Rashid Mezher, the lead judge in the investigation, the bomb contained between 550 and 650 pounds (250 to 300 kg) of explosives. It left a 20-foot wide crater eight feet deep in the boulevard in front of the once grand St. George hotel, which was still under renovation after the 1975-90 civil war.

The Lebanese army was on full alert Tuesday at the start of three days of mourning over the death of Hariri. Schools, shops, private and public institutions were closed for the day.

'Just punishment'
A man claimed responsibility for the attack in a statement aired on Arab-language television network Al-Jazeera Monday.

Identifying himself as Ahmad Abu Adas, the man read a statement claiming responsibility on behalf of a previously unknown group called Victory and Jihad. He said the bombing was a "just punishment" for Hariri's close ties to the Saudi government.

Mezher said Adas is believed to be Lebanese. Authorities have searched his home, but he was not there. Of the four people questioned by authorities, all are associates of his and all but one have been released.

In the hours immediately following the bombing, officials suggested they had a suspect in custody.

The bombing conjured up images from more than a decade ago, when car bombs were used by militias as a weapon of choice to plunge Lebanon into chaos.

"I haven't seen anything on this scale in Beirut since the dark days of the civil war