Syrian military and rebels battle north of Hama

AMMAN (Reuters) -Intense airstrikes and the arrival of pro-government reinforcements drove Syrian rebels back overnight from the edge of Hama, a major city whose fall would pile pressure on President Bashar al-Assad, both sides said on Wednesday.

Rebels have staged their biggest advance in years over the past week, seizing Aleppo - Syria's largest city before the war - and much of the surrounding countryside. By Tuesday they had all but reached the Hama outskirts a third of the way between Aleppo and Damascus.

U.N. Syria envoy Geir Pedersen warned the Security Council on Tuesday that the situation was "extremely fluid and dangerous", adding that Syria faced danger of "further division, deterioration, and destruction".

Any prolonged return of fighting in Syria risks further destabilising a region roiled by conflicts in Gaza and Lebanon.

Syria's civil war killed hundreds of thousands of people, sent many millions fleeing across borders and drew in regional and global powers since 2011, before frontlines were largely frozen years ago with Assad in control of most territory and all major cities.

State media and the Syrian Observatory for Human Rights war monitor said there had been intense fighting over Jabal Zain al-Abidin, a hill 5km (3 miles) northeast of Hama and overlooking a major road into the city.

Abu al-Qaqaa, a rebel commander in the area, said: "We were forced to retreat under heavy enemy bombardment by air." Another rebel source cited the failure to capture Jabal Zain al-Abidin as a setback in the insurgent advance on Hama.

Iran-backed Afghan and Iraqi militia helped reinforce the government's frontlines at Hama, where army units had regrouped after losing Aleppo, rebel and army sources said. Syrian state media reported reinforcements arriving on Tuesday.

The rapid rebel advances have concerned Assad's allies, with Iran saying on Tuesday it would consider sending forces if asked, and Russia saying it would strongly support efforts to "counter terrorist groups and restore constitutional order".

Iran-backed Iraqi fighters this week moved into Syria in support of Assad, whose government has started a new conscription push with checkpoints in Damascus and eastern Deir al-Zor signing up young men to join the army, residents said.

Russian and government bombardment of the rebel enclave in the northwest has intensified over recent days, with airstrikes targeting residential areas and medical centres in Aleppo and Idlib, residents and rescue workers have said.

Reuters could not immediately reach Syrian authorities. Damascus rarely comments on specific allegations but it has previously said it does not target civilians and that accusations against its forces are part of efforts to undermine Syria.

Families who had returned to homes in areas recaptured by the rebels after having fled government advances earlier in the conflict were again forced back by heavy airstrikes, two people in the northwest said.

ALLIES

Russia and Iran, allies of the Assad dynasty for decades, were vital in helping Damascus claw back most of the country from 2015-20 after losing swathes of territory to rebels in the war's early years.

However, Russia has been focused on the war in Ukraine while Iran has been tied up by the conflict in Lebanon, where Israel has inflicted heavy losses on its main regional ally Hezbollah, wiping out most of its leadership in the last two months.

Syria remains important to both its allies. Assad represents an important link in the network of Shi'ite groups Tehran backs across the region. Russia operates a Mediterranean naval port at Tartous and has an air base at Hmeimim near Latakia.

Russian Foreign Ministry spokeswoman Maria Zakharova blamed unidentified foreign powers for the rebels' sudden advance.

"They would not have dared to commit such an audacious act without the instigation and comprehensive support of external forces," she said, adding without providing evidence that rebels had also received drones and training from Ukraine.

Syria's frontlines had settled after an agreement between Russia, Iran and Turkey in 2020.

The strongest rebel faction in the northwest is al-Qaeda's former affiliate Hayat Tahrir al-Sham, which fights alongside several other more mainstream groups that are backed by Turkey.

Ankara also supports the Syrian National Army, a separate rebel grouping that holds a strip of territory along the border. It wants to keep Kurdish groups in Syria away from the frontier and to create a haven for Syrian refugees now living in Turkey.

The main Kurdish armed group leads an alliance backed by the United States, which still has a small contingent of troops on the ground after intervening to help defeat Islamic State, which ran a jihadist mini-state in Syria and Iraq from 2014-2017.

(Reporting by Suleiman al-Khalidi in Amman and Clauda Tanios in DubaiWriting by Angus McDowallEditing by Janet Lawrence and Peter Graff)