A top regime intelligence chief was also killed when Jabhat Fateh al-Sham attacked regime-controlled security installations in the western city of Homs.
At least 42 people including a top regime official were killed on Saturday in the Syrian city of Homs when rebel group Jabhat Fateh al-Sham attacked two regime military and security bases with guns and suicide bombers.
The regime's head of military security General Hassan Daabul, a close confidant of Bashar al-Assad, was also killed in the attack.
At least 29 others were also killed at one of its headquarters in the city and 12 more at a regime security installation, according to the Britain-based Syrian Observatory for Human Rights (SOHR).
"There were at least six attackers and several of them blew themselves up near the headquarters of state security and military intelligence," SOHR director Rami Abdel Rahman said.
Rebel alliance, Tahrir al-Sham, said in a social networking post that five suicide bombers had carried out the attack, but it stopped short of explicitly claiming responsibility.
"Five suicide bombers attacked two branches of state security and military security in Homs ... thanks be to God," the group said in a statement on the Telegram social network.
Tahrir al-Sham was formed in January 2017 out of six factions, including Jabhat Fateh al Sham - which used to be called Jabhat al Nusra and was affiliated with Al Qaeda.
Homs has been under the full control of the regime since May 2014 when rebels withdrew from the centre under a UN-brokered truce deal.
TRT World's Abubakr Al Shamahi has more details from Gaziantep.
Regime air strikes in Hama
At least eight members of the same family were killed and many others wounded in regime air strikes in the western province of Hama on Saturday, SOHR reported.
The war monitor said the victims included six children and their parents.
Hama province is under regime control, but parts of its northern countryside have been held by rebels since 2012.