Updated 4:05 AM ET
BEIRUT Protesters burned tires and set up roadblocks around Lebanon on Saturday in a sign of boiling anger over a massive car bomb that killed a top security official and seven other people a day earlier a devastating attack that threatened to bring Syria's civil war to Lebanon.
The Lebanese Cabinet was scheduled to hold an emergency meeting Saturday as the country's opposition called for Prime Minister Najib Mikati to resign. The state-run National News Agency said security commanders would attend the meeting to discuss how to keep the peace.
The government declared a national day of mourning for the victims, who included Brig. Gen. Wissam al-Hassan, head of the intelligence division of Lebanon's domestic security forces. Dozens were wounded in Friday's blast in Beirut's mainly Christian Achrafieh neighborhood.
Many observers said the attack appeared to have links to the Syrian civil war, which has been raging for 19 months. Al-Hassan, 47, headed an investigation over the summer that led to the arrest of former Information Minister Michel Samaha, one of Syrian President Bashar Assad's most loyal allies in Lebanon.
Samaha, who is in custody, is accused of plotting a campaign of bombings and assassinations to spread sectarian violence in Lebanon at Syria's behest. Also indicted in the August sweep was Syrian Brig. Gen. Ali Mamlouk, one of Assad's highest aides.
Lebanon's fractious politics are closely entwined with Syria's. The countries share a web of political and sectarian ties and rivalries, often causing events on one side of the border to echo on the other. Lebanon's opposition is an anti-Syrian bloc, while the prime minister and much of the government are pro-Syrian.
The civil war in Syria has laid bare Lebanon's sectarian tensions as well.
Many of Lebanon's Sunnis have backed Syria's mainly Sunni rebels, while Shiites have tended to back Assad. Al-Hassan was a Sunni whose stances were widely seen to oppose Syria and the country's most powerful ally in Lebanon, the Shiite militant group Hezbollah.
On Friday, protesters in mostly Sunni areas closed roads with burning tires and rocks in Beirut, the southern city of Sidon, the northern city of Tripoli and several towns in the eastern Bekaa Valley.
The highway linking central Beirut with the city's international airport was closed, as well as the highway that links the capital with Syria, the officials said on condition of anonymity in line with regulations.
Rafik Khoury, editor of the independent Al-Anwar daily, said the assassination was an attempt to draw Lebanon into the conflict in Syria, which has been the most serious threat to the Assad family's 40-year dynasty.
"The side that carried the assassination knows the reactions and dangerous repercussions and is betting that it will happen. Strife is wanted in Lebanon," Khoury wrote.