Free Syrian Army is moving its command center from the Turkish border into Syria itself in preparation of an offensive against Assad's gangs in Damascus.
Riyad al-Asaad, commander of the Free Syrian Army (FSA), announced the move on Saturday in a video message from Syria.
"To the Syrian people, its freedom fighters and all the armed factions, we are glad to let you know that the leadership of the FSA has moved into Syria following arrangements made with other brigades that included securing liberated areas with the hope of launching the offensive on Damascus," Asaad said.
"Since we left our country we suffered all sorts of regional and international interference and political pressure, we were isolated. Their goal was to have the FSA replace Assad once he is gone, but we categorically made it clear that we would never betray our people reiterating that only the Syrians should decide their future institutions."
In Saturday's other developments, Syrian freedom fighters and Assad's gangs clashed near a border crossing with Jordan.
The fighting, accompanied by heavy shelling from Assad's gangs, raged on Saturday near the busy Al-Nasib border crossing located on a highway linking the Syrian and Jordanian capitals.
Meanwhile, freedom fighters shot down a Russian fighter jet as it flew over the northern town of Atarib in Idlib province. They were attacking an enemy military base near the town when the Russian jet flew over and freedom fighters shot it down with anti-aircraft guns.
Vastly outgunned, freedom fighters need surface-to-air missiles to take down Russian fighter jets and helicopters used by the Assad gangs to bombard opposition strongholds.
Fighters use outdated anti-aircraft machine guns that are welded to pickup vehicles but they are inaccurate and useless if the Russian aircraft fly above a certain altitude.
On August 27 fighters shot down a Russian helicopter on the outskirts of Damascus and three days later they had brought down a Russian jet in Idlib, near the Turkish border.
Elsewhere in Syria, Russian-made Alawite jets bombarded areas in Yabroud, near the capital Damascus, and liberated districts in the embattled northern city of Aleppo.
At least 150 people, mainly near Damascus and Aleppo, were killed by Alawites across Syria on Friday.