The move puts Damascus on track to have all its forces out before Lebanese parliamentary elections in May - a key US and UN demand.
Immediately before the February assassination of former prime minister Rafiq al-Hariri, about 14,000 Syrian troops were in Lebanon. At their peak they numbered about 40,000.
On Monday, Syrian soldiers dismantled eight positions near the eastern city of Baalbak, while about 25km to the north in Chaat, more troops loaded goods into 10 trucks, each towing an anti-aircraft gun.
An official said the Lebanese-Syrian Military Commission will meet next week to agree on the second phase of the military withdrawal, which is expected to see the complete removal of Syrian forces from Lebanon.
About 4000 soldiers left in the withdrawal's first phase that ended on 17 March.
Pro-Syrian Lebanese Defence Minister Abd al-Rahim Murad said the pullout would continue "until all the Syrian army has entered Syrian territory".
And Syrian political analyst Imad Fawzi al-Shuaibi said: "The full pullout from Lebanon will remove any pretext claiming that Syria influences Lebanese elections."
"The full pullout from Lebanon will remove any pretext claiming that Syria influences Lebanese elections"
Imad Fawzi al-Shuaibi,
Syrian political analyst
He added: "Syria wants to push away any possibility of being a target for US or international pressures."
Meanwhile, visiting US envoy David Satterfield said the polls must be held on time with international observers monitoring.
"We have said many times that the international community wishes to see Lebanon move forward in a political process which leads rapidly to elections as scheduled," he said.