AMMAN, Sept 1 (Reuters) - Russian military police on Wednesday began patrolling the last rebel bastion in Syria"s southwest under a deal that halted an Iranian-backed government offensive to retake the birthplace of the 2011 popular uprising, military and civilian sources said. Russian generals brokered the deal late on Tuesday to avert bloody urban warfare after the heaviest bombardment by elite Fourth Division government forces of the rebel core of the city of Deraa in a two-month siege. L1N2Q2278 Russian troops hoisted the Russian and Syrian flags inside the Deraa al Balaad district, where the first peaceful protests against Assad family rule in 2011 broke out before security forces cracked down and the unrest morphed into civil war. Under the deal, local rebels began to hand over light weapons based on assurances that Russian military police would maintain patrols and checkpoints to bar Iranian-backed militias from entering, preventing feared reprisals, negotiators said. President Bashar al-Assad"s army said the agreement finally restored state authority to an area where lawlessness had long prevailed. Some residents of the longtime rebel redoubt were jittery and upset about the new arrangement. "It is a sad day to see the flag of the Russian occupier and the criminal regime in the cradle of the revolution that has seen tens of thousands die for its cause," Abdallah Aba Zaid, a Deraa resident whose wife and four children died in a Russian air strike on rebel-held Deraa province earlier in the war. In 2018 Syrian President Bashar al-Assad"s army, aided by Russian air power and Iranian-backed militias, retook the southwestern province of which Deraa is the capital and which borders Jordan and Israel"s Golan Heights. Under a Russian-orchestrated deal then, the Western-backed Deraa rebels handed over heavy weapons but were allowed to continue their own administration of Deraa al Balaad. Moscow also gave guarantees to Israel and the United States in 2018 that it would restrain Iranian-backed militias from expanding their influence in the sensitive border region. In talks that yielded this week"s deal, Deraa al Balaad officials told Russian officers that any entry of the militias that have been a feared ally of Assad during the war could lead to reprisals, from a wave of arrests to summary executions. "The Russian military must live up to their commitment to prevent Iran"s militias from sowing destruction here," Abu Yusef Masalmeh, a Deraa al Balaad negotiator, said of the latest deal. The U.S. State Department on Wednesday condemned what it called "the Assad regime"s ruthless assault on Deraa that has killed civilians and displaced thousands". Most of the 50,000 people who inhabited Deraa al Balaad fled after weeks of shelling during which the army prevented food, medical and fuel supplies coming in but opened a corridor for civilians to leave, residents and local officials say. Assad turned the tables against rebel and Islamist groups arrayed against him in the war after Russia intervened on his side in 2015, and has since recaptured about 70% of the country.