At least 14 Syrian security personnel were killed when pro-Assad forces reportedly ambushed them in the southern province of Tartus.
A Syria war monitor said three armed men were also killed in clashes when security forces sought to arrest a former-regime officer, who was linked to a notorious prison.
The Syrian Observatory for Human Rights said "14 members of the General Security force" of Syria's new authorities were killed, along with "three armed men" in Khirbet al-Maaza, raising an earlier toll of nine dead.
Forces had sought to arrest an officer who was among "those responsible for the crimes of the Saydnaya prison," added the Observatory.
New Interior Minister Mohammed Abdel Rahman said in a statement that "14 interior ministry personnel were killed and 10 others wounded after ... a treacherous ambush by remnants of the criminal regime" in Tartus province "while performing their tasks of maintaining security and safety."
The doors of Syria's prisons were flung open after the anti-regime force led by Hayat Tahrir al-Sham (HTS) ousted Assad this month, more than 13 years after his brutal repression of anti-government protests triggered a war that has killed more than 500,000 people.
The Observatory said the wanted man was "an officer in the former regime forces who held the position of director of the military justice department and field court chief," identifying him as Mohammed Kanjo Hassan.
It said he "issued death sentences and arbitrary judgment against thousands of prisoners."
The clashes in Tartus province – a stronghold of Assad's Alawite minority – erupted after "a number of residents refused to allow their houses to be searched," said the Britain-based Observatory, which relies on a network of sources inside Syria.
The officer's brother and armed men intercepted the security forces, "set up an ambush for them near the village and targeted one of the patrol vehicles," the Observatory said.
It added that "dozens of people" were arrested in the village.
The notorious Saydnaya complex, the site of extrajudicial executions, torture and forced disappearances, epitomized the atrocities committed against Assad's opponents.
The fate of tens of thousands of prisoners and missing people remains one of the most harrowing legacies of the conflict.
