Prime Minister Najib Miqati signed on Tuesday the decree to refer the case of the assassination of Internal Security Forces Intelligence Bureau head Wissam al-Hasan's to the judicial council.

The decree has also been referred to President Michel Suleiman.

The March 14 alliance is pressing forward with its decision to topple the cabinet as it will boycott any official activity, including the parliament, An Nahar newspaper reported on Tuesday.

Lawmakers affiliated with the March 14 parliamentary blocs boycotted Tuesday's joint parliamentary committees meeting, which is set to tackle the new electoral draft law.

EU foreign policy chief Catherine Ashton warned on Tuesday against a political vacuum in Lebanon after the opposition March 14 camp called for Premier Najib Miqati to step down over the assassination of Intelligence Bureau chief Maj. Gen. Wissam al-Hasan in a car bombing blamed on Syria.

Ashton met with Miqati at the Grand Serail, President Michel Suleiman at the Baabda palace and Speaker Nabih Berri at Ain el-Tineh.

Interior Minister Marwan Charbel revealed that investigations into the assassination of Internal Security Forces Intelligence Bureau chief Brigadier General Wissam al-Hasan is making “speedy progress”, revealing that they have reaching important information in the case, reported the pan-Arab daily Asharq al-Awsat on Tuesday.

Security information revealed that the owner of the stolen car that was booby-trapped in the bombing that killed Hasan on Friday has been identified.

The assassination of Internal Security Forces Intelligence Bureau head Brigadier General Wissam al-Hasan postponed the release of the remaining Lebanese pilgrims who were kidnapped in Syria in May.

According to al-Joumhouria newspaper on Tuesday, the bombing in Beirut's Ashrafiyeh district on Friday suspended the initiative “circumstantially.”

Special Tribunal for Lebanon spokesman Marten Youssef said on Tuesday that referring the assassination of Internal Security Forces Intelligence Bureau head Brigadier General Wissam al-Hasan requires a decision by the United Nations Security Council.

If the Security Council decided to refer this crime or other crimes to the STL then it will work on accomplishing that, Youssef said in comments published in As Safir.

The United States will send a Federal Bureau of Investigation team to help Lebanon probe Ashrafiyeh car bombing that killed Internal Security Forces Intelligence Bureau head Brigadier General Wissam al-Hasan, officials said Monday.

But U.S. Secretary of State Hillary Clinton stressed Washington's support for Lebanon's sovereignty, in a phone call with Prime Minister Najib Miqati, State Department spokesman Mark Toner said.

The Lebanese Forces parliamentary bloc on Monday stressed that the bomb attack that killed Intelligence Bureau chief Maj. Gen. Wissam al-Hasan and three other people “requires rejecting the conventional approaches” towards such incidents.

In a statement issued after an emergency meeting in Maarab headed by LF leader Samir Geagea, the bloc said “the call for speeding up investigations into this crime is an approach that did not solve the mystery of any of the previous bombings, knowing that the martyr Major General was the one behind unveiling some of the plots that others sought to conceal.”

Prime Minister Najib Miqati on Monday warned that “irresponsible street action serves the plot of the criminals who want to drag the country into chaos and strife," one day after angry mourners tried to storm the Grand Serail – the government's headquarters – and in the wake of deadly clashes in Tripoli and Beirut.

“The objective behind the assassination of (Intelligence Bureau chief) Maj. Gen. (Wissam) al-Hasan is undermining stability and civil peace,” Miqati said on the social networking website Twitter.

The Palestinian factions in Lebanon on Monday issued a joint statement stressing that any of their members did not take part in the clashes that erupted in Beirut overnight Sunday, after the Army Command said a Palestinian gunman was killed in an exchange of gunfire with an army patrol.

Al-Jadeed television had reported that Palestinian fighters were involved in the violence.