Israeli President Shimon Peres said on Tuesday that Syrian President Bashar Assad has become the "murderer" of his people and they need help to free themselves from his regime.

"Their president, who is supposed to be the father of their nation, became their murderer," Peres told reporters during a joint press conference with visiting German President Joachim Gauck.

The mysterious case of 11 Lebanese Shiites who were taken hostage in Syria last week is raising fears of renewed street battles in Beirut as Lebanon increasingly gets drawn into the swirling chaos next door.

The Syrian crisis already has spilled across the border into Lebanon over the past three weeks, sparking deadly violence in a country that remains deeply divided over the 15-month-old uprising against Syrian President Bashar Assad.

Syrian Ambassador to Lebanon Ali Abdul Karim Ali stated on Tuesday that the discovery of the Lutfallah II ship that was smuggling arms to Syria was among the factors that prompted the Syrian Ambassador to the United Nations Bashar al-Jaafari to send a letter to U.N. chief Ban Ki-moon complaining about Lebanon’s alleged harboring of “terrorist elements.”

Ali stated after holding talks with Foreign Minister Adnan Mansour: “Jaafari’s letter is based on facts on the ground in Lebanon.”

Most of the victims of the massacre in the Syrian town of Houla were summarily executed, the U.N. rights body said on Tuesday, amid global outrage over the killings.

"It's believed that under 20 of the 108 killings can be attributed to artillery and tank fire," said Rupert Colville, spokesman for the United Nations High Commissioner for Human Rights.

At least 19 people were killed in violence on Tuesday in Syria, where clashes between regime troops and rebels raged, monitors said.

In central Homs province, seven civilians were killed overnight, the Syrian Observatory for Human Rights said. Three of them died when the army shelled the outskirts of restive Qusayr, while four died in the city of Homs.

Australia Tuesday expelled Syria's top diplomat over the "hideous and brutal" massacre at Houla of more than 100 people, with Foreign Minister Bob Carr saying he expected other countries to follow suit.

Syrian charge d'affaires Jawdat Ali was notified of the decision to expel him and one other diplomat a day after he was called in to meet with officials over the killings which sparked global condemnation.

U.N.-Arab League peace envoy Kofi Annan urged Syrian President Bashar Assad to "act now" to end 15 months of bloodshed, during a meeting in Damascus on Tuesday.

"I appealed to him for bold steps now -- not tomorrow, now -- to create momentum for the implementation of the plan," Annan told reporters in the Syrian capital.

The fate of the 11 abducted Lebanese pilgrims remains unknown as officials confirm that efforts are still ongoing to release the men and that they are in good condition.

“Contacts are ongoing with all sides to determine (the fate of the pilgrims) and we ensure their families that they are fine and safe,” Prime Minister Najib Miqati told As Safir on Tuesday.

Britain summoned Syria's top diplomat in London to the foreign ministry on Monday to protest against the "sickening and evil" Houla massacre of more than 100 people, the government said.

Syria's charge d'affaires -- their ambassador has been withdrawn -- was warned during the meeting with a top Foreign Office diplomat that the international community would take further action if Damascus does not implement U.N.-Arab League envoy Kofi Annan's peace plan.

The United Nations, not Syria, must investigate the Houla massacre, Human Rights Watch said adding that witness testimony suggest government forces were responsible for the carnage.

"Kofi Annan should push Syria's government to allow the U.N.-appointed Commission of Inquiry access into the country to investigate," the massacre in which at least 108 people were killed, including 49 children.