A Kurdish-led coalition of armed groups has made advances in northern Syria as it continues a campaign to evict the Islamic State of Iraq and the Levant (ISIL, or ISIS) armed group from its stronghold in the city of Raqqa.

The Syrian Democratic Forces (SDF), took control of the Namrodia and Matmashraja villages near Ain Issa, some 55km north of Raqqa, Syrian state news agency SANA reported on Wednesday.

US-led forces also carried out air strikes targeting ISIL positions in the countryside of Raqqa, according to activist groups.

The SDF, a US-backed coalition of Kurdish and Arab fighters headed by the Kurdish People's Protection Units (YPG), mobilised thousands of fighters and launched a military offensive in Raqqa on Tuesday.

READ MORE: In Raqqa, support ISIL or die

ISIL has imposed strict rule in Raqqa - home to more than 220,000 people before the Syrian conflict - and committed atrocities against the civilian population since its takeover of the city more than two years ago.

As clashes intensified between SDF forces and ISIL fighters in Raqqa's northern countryside, the activist group Raqqa Is Being Slaughtered Silently reported on Twitter that ISIL prevented civilians from fleeing the city.

Earlier in the day, the same group said ISIL allowed civilians to flee to Deir Az Zor, another area with territory under the armed group's control.

The UK-based Syrian Observatory for Human Rights said SDF forces made advances in al-Haisha village as US-led coalition forces carried out several air strikes on ISIL positions.

the only way to get our of #Raqqa now is throw Smugglers it cost 400$ for the 1 person #Syria #ISIL #ISIS — الرقة تذبح بصمت (@Raqqa_SL) May 25, 2016

Raqqa Is Being Slaughtered Silently also said that more than 100 people have joined ISIL since the offensive started on Tuesday, noting that local civilians harbour a deep-seated distrust of Kurdish armed groups.

#Raqqa the strategy of taking Raqqa by #SDF Which are managed by #YPG push a lot of people to join #ISIS to Defense for their city #Syria — الرقة تذبح بصمت (@Raqqa_SL) May 24, 2016

On Tuesday, Russian Foreign Minister Sergey Lavrov announced that Russia - a staunch ally of Syrian President Bashar al-Assad - was prepared to coordinate with US-led coalition forces to evict ISIL from Raqqa.

"Raqqa is one of the aims of the anti-terrorist coalition, just like Iraq’s Mosul," Lavrov said. "We are confident that these cities could have been liberated more effectively and faster if our military officials would have started coordinating their actions much earlier."