The White House has condemned "in the strongest terms" what it calls a terrorist attack in Beirut that killed a top security official and seven others.
In a statement, National Security Council spokesman Tommy Vietor said the United States will stand with the Lebanese government to bring to justice those responsible "for this barbaric attack," which killed the head of the intelligence division of Lebanon's domestic security forces, Brigadier-General Wissam al-Hassan.
The UN Security Council also denounced the blast, which occurred on October 19
Guatemalan ambassador and acting Security Council President Gert Rosenthal read out a Security Council statement, which "strongly condemned the terrorist attack...which killed Brigadier General Wissam al-Hassan...and caused numerous deaths and injuries, including among civilians."
Hassan led the investigation that implicated Syria and Hizballah in the assassination of former Prime Minister Rafik al-Hariri.
Lebanon's opposition March 14 bloc said it held Prime Minister Najib Mikati responsible for the death of Hassan and called on his government to resign.
Mikati said the government was trying to find out who carried out the attack and said those responsible would be punished.
French President Francois Hollande urged Lebanese politicians to stay united and prevent attempts to destabilize the country.
The attack prompted Sunni Muslims to take to the streets in areas across the country, burning tires in protest.
Saad al-Hariri, the son of Hariri, accused Syrian President Bashar al-Assad of killing the top intelligence official.
Syria has for a long time played a major role in Lebanese politics, particularly during Lebanon's 1975-1990 civil war. Syrian troops occupied parts of the country during that war, and remained in Lebanon until 2005.
Analysts are calling the attack in Beirut a spillover from the bloodshed in neighboring Syria.
The conflict there has pitted mostly Sunni insurgents against Assad, who is from the Alawite sect linked to Shi'ite Islam.
In Lebanon, the Syrian conflict has split the country's religious communities between those supporting Assad and those backing the rebels trying to overthrow him.
With reporting by Reuters, dpa, and AP