But, he said, its soldiers “rely morally and psychologically on something like a truce, like surrender, like destroying the enemy, and in this kind of war you are not really able to measure your success.”

Since early in the conflict, large numbers of military-age men have paid thousands of dollars to legally avoid military service — so many that analysts say the fees have constituted a significant revenue stream for a government that is determined to keep paying salaries to show that it remains in control.

The government has long lacked enough reliably loyal troops to blanket contested areas with patrols or take them with ground operations, so instead it has relied on indiscriminate airstrikes and artillery attacks that have pushed the death toll well above 70,000, according to United Nations estimates. Rebels say fighters from the Lebanese militant group Hezbollah have increased their presence to buttress government troops.

But now, to fill the gap further, the government is increasingly relying on paramilitary groups, according to analysts and a recent United Nations report.

The groups began as the pro-government militias known as shabiha, some of them given formal status as Popular Committees. In recent months they have been organized under a structure called the National Defense Forces. The United States government has accused Iran, Syria’s ally, of helping build the groups on the model of Iran’s feared Basij militia.

In government-controlled areas of Aleppo, Syria’s largest city, many of the ubiquitous checkpoints are now operated by those groups — usually made up of locals — rather than the army, said Peter Harling, the Syria analyst for the International Crisis Group, a conflict-monitoring organization. As people lose faith in the army, they are loath to risk death on far-flung army deployments, he said, while “holding your ground, protecting your own neighborhood, is far more appealing.”

The pro-government newspaper Al Watan declared Tuesday that the army had “at its disposal enough men and weapons to fight for years to defend Syria.”