Bombardments come as Syrian government forces continue to push rebel groups from last strongholds near Damascus.

Syrian government forces continue to launch air strikes on ISIL-held pockets in Hajar al-Aswad, one of the neighbourhoods of the besieged Palestinian refugee camp of Yarmouk.

The strikes on Sunday are part of a campaign to retake the last rebel-held towns on the outskirts of the capital, Damascus, which has seen a dramatic increase of violence over the last weeks.

Since the beginning of the campaign on April 19, at least 18 civilians have been killed, activists in nearby rebel-held towns told Al Jazeera.

The ongoing bombardments have prompting fresh warnings by the United Nations about a looming humanitarian disaster in the area.

As Syrian President Bashar al-Assad’s forces battled to retake Hajar al-Aswad and Tadamun, areas that make up a considerable chunk of Yarmouk, the Syrian army said on Saturday it retook control of the Qadem district, state-run news agency SANA reported.

Before the Syrian war started in 2011, Yarmouk was home to Syria’s largest Palestinian refugee population.

In the years that followed, most of its 160,000 residents fled to other parts of Syria or to neighbouring countries.

In 2015, Yarmouk came under control of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group at the height of its power.

It has over the past week seen a dramatic increase in violence. According to the United Nations, 1,200 civilians remain trapped inside, mostly in the basements of their homes, without access to food or medicine.

“Yarmouk and its inhabitants have endured indescribable pain and suffering over years of conflict. We are deeply concerned about the fate of thousands of civilians, including Palestine refugees, after more than a week of dramatically increased violence,” Pierre Krahenbuhl, commissioner-general of UNRWA, the UN agency responsible for Palestinian refugees, said in a statement.

The camp has been under a government-imposed siege since 2012. At least 180 civilians have died of hunger in 2014, while others suffered illnesses including salmonella poisoning, kidney failure and typhoid fever, according to activists and medics.

Aid groups have decried the situation of Palestinian refugees and Syrians in the area, as activists accuse forces loyal to Assad of using surface-to-surface missiles, barrel and cluster bombs, as well as mortar fire.

UK-based Action Group for Palestinians of Syria estimates that 60 percent of Yarmouk has been destroyed and many have fled the camp.

Areas under attack

The offensive on Yarmouk comes after government forces captured Eastern Ghouta, a Damascus suburb and one of the last rebel-held strongholds in the war-torn country.

Syrian forces allegedly used chemical weapons during a seven-week standoff that resulted in an evacuation deal between Russia and Jaish al-Islam, the last armed opposition group to have remained in Eastern Ghouta – which was under rebel-control since 2012.

In the northwest, Syrian and Russian warplanes are also bombarding the last major rebel-held city, Idlib, which is controlled by a coalition of rebel forces, including the Free Syrian Army and Ahrar al-Sham.

Idlib is housing an estimated two million people, including thousands who became internally displaced from other parts of Syria.

French Foreign Minister Jean-Yves Le Drian has warned of a humanitarian disaster in the city.

Syria has been in a state of war since 2011 after authorities used lethal force to crack down on nonviolent protests against the Assad government.

The conflict later escalated into a regional proxy war that has killed at least 500,000 people, displaced millions and created a refugee crisis.

The Syrian government and allied forces are also attacking ISIL in the Deir Az Zor region, where the group holds several pockets after being pushed out of the regional capital in late 2017.