Syrian troops aided by Russian air strikes fought their fiercest clashes with rebels in weeks on Monday, as Europe's top diplomats demanded that Moscow stop targeting non-jihadist rebels.

Meeting in Luxembourg, European Union foreign ministers also said lasting peace in Syria was impossible without a transition from President Bashar al-Assad's rule.

Baghdad, meanwhile, said it was trying to confirm reports that Islamic State jihadist group leader Abu Bakr al-Baghdadi had been wounded in an Iraqi strike on his convoy.

On the ground in Syria, the army command said regime forces had captured Kafr Nabuda village in central Hama province, extending their advance in the region around the strategic Damascus-Aleppo highway.

Regime forces have been pushing an offensive on both sides of the highway towards the town of Khan Sheikhun, just over the provincial border in Idlib.

The Syrian Observatory for Human Rights monitor said clashes were ongoing in Kafr Nabuda, adding that Russian warplanes had carried out at least 20 strikes in and around the village.

"The clashes are the fiercest since the Russian air campaign began on September 30," Observatory chief Rami Abdel Rahman said.

- Renewed Russian strikes -

Many of Russia's air strikes so far have been focused on the area where Hama, Idlib and Latakia provinces meet.

Latakia province on the Mediterranean coast is a stronghold of the regime and the home of Assad's ancestral village.

Idlib province is controlled by the powerful Army of Conquest rebel alliance which includes Al-Qaeda affiliate Al-Nusra Front.

In recent months, the alliance has sought to expand from Idlib into Hama and the strategic Sahl al-Ghab plain between the three provinces in a bid to target Latakia.

Abdel Rahman said the rebels were sending reinforcements to Kafr Nabuda to battle the regime, which was also shelling other parts of Hama and Latakia provinces.

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 city in the north.

The 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 Aleppo.

A military source said the advance by regime forces 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.

Citing a military source, Syria's state television said on Monday that Russian strikes had targeted command centres and training camps, including one that had as many as 1,200 "terrorists" inside.

Russia's air strikes in Syria began on September 30, with Moscow saying it was targeting IS and other "terrorists".

But rebels and their backers accuse Moscow of focusing on moderate and Islamist opposition fighters, rather than jihadists.

- EU concern on targets -

The EU on Monday expressed "deep concern" about the focus of Russia's strikes.

EU foreign policy chief Federica Mogherini called Russia's military intervention in Syria a "game-changer" that jeopardised peace efforts and risked clashes with Western aircraft also targeting IS.

"The recent Russian military attacks that go beyond Daesh (Islamic State) and other UN-designated terrorist groups, as well as on the moderate opposition, are of deep concern and must cease immediately," the EU's 28 foreign ministers said in a statement.

The statement also reiterated the need for a political transition in Syria 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 ministers said.

More than 240,000 people have been killed in Syria's conflict and upwards of four million Syrians have become refugees.

The war has fractured the country and attracted thousands of foreign fighters to the ranks of jihadist groups such as IS, which controls swathes of territory in Syria and neighbouring Iraq.

In Baghdad, security services said Monday they were checking reports that IS 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," interior ministry spokesman Saad Maan told AFP.

Iraq's security forces said Sunday that Iraqi warplanes had struck Baghdadi's convoy as it was heading to an IS leadership meeting in Karabla near the border with Syria.

But such claims have been made in the past and never verified, and pro-IS social media accounts mocked the latest reports.