European Union foreign policy chief Catherine Ashton is visiting Beirut for talks with Lebanese Prime Minister Nagib Mikati. She was due to discuss ways to reduce sectarian tensions and the plight of Syrian refugees.
The Lebanese news agency NNA reported Tuesday that several grenades had been fired off overnight from Syria landing on Lebanese territory. They had hit three villages in the Akkar district, but noone was hurt.
The Lebanese army said it was determined to restore order. It has deployed troops in Sunni areas of the capital Beirut.
The latest violence erupted after the killing of the intelligence chief of the Internal Security Forces, Wissam al-Hassan, by a car bomb in Beirut on Friday.
Sunnis in Lebanon were quick to blame the assassination on neighboring Syria, as al-Hassan, a Sunni, was noted for pursuing alleged Syrian crimes in Lebanon including the 2005 assassination of former premier Rafiq Hariri.
The latest assassination drew international condemnation and US officials have said they would send a team from the Federal Bureau of Investigation to help with the criminal investigation.
Lebanon is a country in which Christians, Shiite and Sunni Muslims who each make up about one-third of the population. Political life is governed by power sharing agreements.
Sunday's funeral for al-Hassan had been billed as an opportunity to protest against Syrian meddling in Lebanon. But the mood quickly turned against the Lebanese government and sparked calls for Mikati, whose cabinet is dominated by Syria's ally Hezbollah, to resign.
Hezbollah's militia, which never disarmed after the 1975-90 civil war, is the most powerful military force in Lebanon.
Syrian violence spilling across the border
Tensions in Syria where a 19-month-old anti-regime revolt has left more than 34,000 people dead, have regularly spilled over into Lebanon.
According to United Nations estimates, there are an estimated 67,000 registered Syrian refugees in Lebanon.
The EU is offering support to deal with the flow of Syrian refugees into Lebanon.
The head of German parliament's foreign affairs committee, Ruprecht Polenz of chancellor Merkel's CDU party, has now spoken out in favor of increasing the number of UN soldiers in Lebanon.
He told the Osnabrücker Zeitung newspaper on Tuesday, that more blue helmet peacekeepers could be sent to the region to help with de-escalation if Lebanon launched a request with the UN.
"The Lebanese army is not strong enough to assert itself in the face of Hizbollah threats," Polenz said.
The German Bundeswehr has over 180 soldiers stationed in Lebanon as part of the UNIFIL mission there.
rg/ipj (AFP, dpa)