The White House says those responsible for Monday's bombing in Lebanon must be punished for the murder of the former prime minister and others caught in the brutal attack on the city's center.

"The United States will consult with other governments in the region and on the Security Council today about measures that can be taken to punish those responsible for this terrorist attack, to end the use of violence and intimidation against the Lebanese people and to restore Lebanon's independence, sovereignty and democracy by freeing it from foreign occupation," White House press secretary Scott McClellan said.

McClellan said it's unclear who was responsible for the bomb attack on former Prime Minister Rafik Hariri's (search) motorcade and he refused to speculate whether Syria or its ally, Iran, was behind it. Before he resigned last fall, Hariri often defied Syria (search), which dominates Lebanon politically and militarily. The United States has long called for Syria to leave Lebanon.

"It's premature to know who was responsible for this attack, but we continue to be concerned about the foreign occupation in Lebanon," McClellan said. "We've expressed those concerns. Syria has maintained a military presence there for some time now, and that is a concern of ours."

McClellan would not reveal whether it was discussing sanctions with the Security Council, but said there should be a response to the prime minister's death.

"This is a despicable act, and it took many lives or many injured and a number of others," he said. "And we condemn it in the strongest possible terms."

Hariri's motorcade of bulletproof vehicles was hit Monday afternoon as it traveled through Beirut. At least 20 cars were set on fire in a blast that injured about 100 people, left a 30-foot crater in the street and damaged a British bank and the landmark Phoenicia Hotel (search) along the Mediterranean waterfront.

McClellan said President Bush was shocked and angered by the attack.

"Mr. Hariri was a fervent supporter of Lebanese independence and worked tirelessly to rebuild a free, independent and prosperous Lebanon following its brutal civil war and despite its continued foreign occupation," McClellan said. "His murder is an attempt to stifle these efforts to build an independent sovereign Lebanon free of foreign domination."