BEIRUT (AFP) - Regime troops aided by Russian air strikes fought their fiercest clashes with rebels in weeks Monday, as US-led coalition forces parachuted ammunition to rebels battling extremists in northern Syria.
Meanwhile, the UN's peace envoy to Syria said he was heading to Moscow to promote a political end to the conflict, despite Russia intensifying its raids.
On Monday, the US said coalition forces had airdropped ammunition to Syrian Arab groups fighting the ISIS (Islamic State in Iraq and Syria) extremist group in northern Syria.
"Coalition forces conducted an airdrop Sunday in northern Syria to resupply local counter-ISIL ground forces as they conduct operations against ISIL," US Central Command spokesman Colonel Patrick Ryder said in a statement, using an alternative acronym for ISIS.
Speaking on condition of anonymity, a US official said the drop included 50 tons of ammunition.
Ryder said the ammunition was for Syrian Arab groups whose leaders were "appropriately vetted by the United States and have been fighting to remove ISIL from northern Syria".
Several Arab rebel groups and Syria's leading Kurdish militia formalised their alliance Sunday in a new group called the Syrian Democratic Forces.
On Monday, Syrian troops and allied forces gained ground in the central province of Hama, advancing on the strategic Sahl al-Ghab plain backed by Russian air power.
Syria's army command said regime forces had captured Kafr Nabuda village in Hama, extending their advance around the key Damascus-Aleppo highway.
And the Syrian Observatory for Human Rights said the Syrian army had captured Mansoura village in the Sahl al-Ghab plain.
"The clashes are the fiercest since the Russian air campaign began on September 30," Observatory chief Rami Abdel Rahman said, adding that dozens of Russian air strikes hit Sahl al-Ghab on Monday.
Sahl al-Ghab lies at the intersection of the provinces of Hama, Latakia and Idlib, and has been a major target for Russian strikes.
Idlib province is controlled by the powerful Army of Conquest rebel alliance which includes Al-Qaeda affiliate Al-Nusra Front.
They have sought to advance into Sahl al-Ghab and on towards Latakia province, the coastal stronghold of the regime and the home to President Bashar al-Assad's ancestral village.
Syria's army command also reported advances in northern Latakia province and said regime forces had taken control of the "duty free zone" outside Aleppo in the north.
Aleppo city is divided between rebel control in the east and government control in the west, while the situation is largely the reverse in the countryside around it.
A military source said the regime advance would help protect territory it holds in the area, including the Sheikh Najjar industrial area to the city's northeast.
Moscow said Monday its air force had hit 53 targets in Syria in the past 24 hours, in Hama, Homs, Latakia and Idlib provinces.
Russia's air strikes in Syria began on Sept 30, with Moscow saying it was targeting ISIS and other "terrorists".
But rebels and their backers accuse Moscow of focusing on moderate and Islamist opposition fighters, rather than extremists.
On Monday, UN peace envoy to Syria Staffan de Mistura said he would head to Moscow then Washington, as he struggles to push his initiative for a political settlement in Syria.
He acknowledged that Russia's air strikes had "introduced new dynamics" to the brutal conflict.
Also on Monday, European Union foreign ministers demanded that Moscow stop targeting non-extremist rebels and said lasting peace in Syria was impossible without a transition from Assad's rule.
"The recent Russian military attacks that go beyond Daesh (ISIS) and other UN-designated terrorist groups, as well as on the moderate opposition, are of deep concern and must cease immediately," the 28 ministers said in a statement.
The statement also reiterated the need for a political transition to end the conflict that began with anti-government protests in March 2011.
"There cannot be a lasting peace in Syria under the present leadership," the EU ministers said.
More than 240,000 people have been killed in the conflict and upwards of four million Syrians have become refugees.
In Baghdad, meanwhile, security services said Monday they were checking reports that ISIS chief Abu Bakr al-Baghdadi had been wounded in a strike on his convoy.
"We are still collecting and cross-checking information to reach an accurate assessment," said interior ministry spokesman Saad Maan.
Iraq's security forces said Sunday Iraqi warplanes had hit Baghdadi's convoy as it was heading to an ISIS leadership meeting in Karabla near the border with Syria.
But such claims have been made in the past and never verified, and pro-ISIS social media accounts mocked the reports.