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.

Progressive Socialist Party leader warned on Monday against forcing the government to “carry more than it can bear” in Lebanon in light of the increased demands for its resignation in the wake of the assassination of Internal Security Forces Intelligence Bureau head Brigadier General Wissam al-Hasan on Friday.

He said in his weekly editorial in the PSP-affiliated al-Anbaa magazine: “Insisting on the government's resignation will lead Lebanon to a vacuum and the country into the Syrian regime's trap.”

The Army Command stressed on Monday that Lebanon's security is a “red line” and it will take strict measures against all those who are targeting security, as Army Commander General Jean Qahwaji inspected the army units deployed in Beirut.

It said in a statement: “We will not allow Lebanon to once again be turned into an open ground for regional conflicts.”

Al-Mustaqbal bloc MP Mohammed Kabbara on Monday called for the government's departure and the formation of a salvation government, urging Tripoli's residents to “fully cooperate with the army in order to restore security,” after four people were killed and 18 others wounded in clashes in the northern city.

“Security in the city of Tripoli is a red line,” said Kabbara, reciting a statement issued after a meeting for Tripoli's dignitaries at his residence.

The ambassadors to Lebanon of the five permanent United Nations Security Council members held talks on Monday with President Michel Suleiman on the current security situation in Lebanon.

U.N. Special Coordinator for Lebanon Derek Plumbly said after the meeting that the five countries support the president's efforts to ease the tensions and put an end to the security chaos.

European Union ambassador to Lebanon Angelina Eichhorst stressed on Monday that the EU voices its full support to the Lebanese state institutions amid the “critical” stage it's passing through, saying that EU foreign policy chief Catherine Ashton will not postpone her scheduled visit on Tuesday.

The EU supports the Lebanese institutions, in particular, the security agencies and the army, Eichhorst said in comments published in As Safir newspaper.

The head of the Syrian National Council Abdel Basset Sayda accused the Syrian regime of being behind the assassination of Internal Security Forces Intelligence Bureau head Brigadier General Wissam al-Hasan, reported al-Joumhouria newspaper Monday.

He warned: “The Syrian regime will commit more assassinations in Lebanon in order to create unrest in the country and cover up its crimes in Syria.”

President Michel Suleiman is seeking to find a solution and counteract the repercussions of the assassination of Brigadier General Wissam al-Hasan, chief of the Internal Security Forces Intelligence Bureau, the al-Joumhouria daily reported Monday.

Sources close to the presidential palace in Baabda told the daily that Suleiman seeks to explore the next phase as Prime Minister Najib Miqati intends to submit his resignation, according to reports, and has decided not to go to his office at the Grand Serail.

Colonel Imad Othman succeeded Brigadier General Wissam al-Hasan as the head of the Internal Security Forces Intelligence Bureau.

Internal Security Forces chief Ashraf Rifi appointed on Sunday night Othman after tackling the matter with Interior Minister Marwan Charbel.