BEIRUT, Lebanon — Commanders of the Free Syrian Army, the main umbrella group for fighters opposing President Bashar al-Assad, said Saturday that they had moved their headquarters from Turkey into “liberated areas” inside Syria, in what they portrayed as a major step forward in their efforts to aid, coordinate and control disparate groups of rebels.

In a video titled “Free Syrian Army Communiqué No. 1 From Inside,” Col. Riad al-Assad, the leader of the Free Syrian Army, declared: “To our free Syrian people and to all free revolutionaries in Syrian towns, villages and suburbs and to all armed factions of the revolution: We announce the entry of the leadership of the Free Syrian Army into liberated territories in Syria.”

The goal, analysts said, appeared to be as much political as military, a bid to win legitimacy and edge out competing exile groups seeking to position themselves as governments in waiting. Fighters and opposition activists in Syria have derided the F.S.A. leaders and other exiles as opportunists, removed from the battle and lacking credibility among the Syrians directly involved in the fighting.

In the video, Colonel Assad sought to assuage those concerns. He emphasized that the move was made “in collaboration with battalions inside Syria.”