"The forces of the Lebanese army are not sufficient to replace the Syrians who might leave the Bekaa Valley (in eastern Lebanon), where they are now concentrated, for good," Defence Minister Abd al-Rahim Murad said on Friday.
"The members of the army are too young to be able to carry out a task that has until now been handled by seasoned soldiers and their numbers are insufficient because we have recently reduced the length of compulsory military service from a year to six months," he added.
Ghassan bin Jiddu, chief of Aljazeera's bureau in Beirut, said Murad is seen as one of Damascus' top allies in Lebanon and has been mentioned as the most likely candidate for the premiership if caretaker Prime Minister Umar Karami does not return to the post.
Aljazeera has learned that Karami will announce on Wednesday or Thursday that he will not form the next government - despite President Emile Lahud inviting him to do so not long after he initially resigned under pressure over the killing of former prime minister Rafiq al-Hariri.
The likely decision to decline comes after a Karami delegate meeting Maronite Christian leader Patriarch Nasr Allah Sfair failed to get his and the opposition's backing for the formation of a new Karami-led government.
Syrian President Bashar al-Asad announced his intention to
withdraw an estimated 14,000 Syrian troops from Lebanon in two stages on 5 March. He later gave a pledge to a UN envoy to abide by terms of UN Security Council Resolution 1559, which calls for a complete pullout.
An estimated four to five thousand Syrian troops have already returned home, with the remaining 10,000 or so concentrated in the Bekaa Valley near the Syrian border.
A joint Lebanese-Syrian military committee is to meet in the first week of April to determine the next move.
The Syrian pullout was undertaken in the face of immense Lebanese and international pressure that followed the assassination on 14 February of al-Hariri.
The Lebanese opposition blames
Syria for al-Hariri's assassination
The attack, blamed by the Lebanese opposition on Syria despite denials by Damascus, inflamed public opinion and galvanised momentum to end the near 30-year Syrian military presence in Lebanon.
Syrian forces entered the country in 1976 to serve as a buffer between warring Lebanese factions and at one time numbered 40,000.
Aljazeera has learned that Syrian troops have evacuated some of their sites in the Bekaa area, including Dair al-Ahmar, al-Labwa, Maqna and Aynata, north of Bekaa, and were returning to Syria.
The troops have also dismantled their artillery in some parts of central Bekaa.
Jumblat wants the resignation
of Lebanon's security chiefs
In other developments, the opposition welcomed the results of the UN report into al-Hariri's assassination which said the Lebanese government's investigation of the incident was flawed.
Lebanese Shia religious leader Muhammad Husain Fadl Allah held the US responsible for incidents taking place in Lebanon, saying they intended to establish a military base to demolish Syria.
And Lebanon's top opposition figure renewed calls on Saturday for the security chiefs to resign to make way for an international investigation into the killing of al-Hariri.
"It is not possible to carry out a just, serious, clear and transparent investigation if the heads of the agencies remain in their place. This is a basic conclusion," Walid Jumblat said.
"We warned against a security state over and over," he added.