Turkish shelling of the Syrian town of Afrin overnight has killed at least 18 civilians, Kurdish forces and a war monitor have said.

The Turkish army and allied Syrian militias have encircled the Kurdish-controlled town and are attempting to storm it from the north, YPG militia spokesperson Brusk Hasakah said on Friday.

Hundreds of families have fled the town for Syrian government controlled areas, the UK-based Syrian Observatory for Human Rights said, as the YPG and its female affiliate the YPJ prepare for a battle to control of the town.

Explosions as Turkey confirms airstrikes on Afrin, Syria

At least 12 people were killed on Thursday.

“Our staff are doing their best, but our rooms are filled with wailing wounded and people in pain, as we lack some medical supplies,” Dr Joan Shitika, head of Afrin hospital, told the German news agency DPA.

Turkey’s two-month-old Operation Olive Branch is aimed at driving Kurdish forces away from the border region between the two countries.

Turkey views the Syrian Kurdish fighters as an extension of its own separatist PKK, a group designated as a terrorist organisation by Ankara as well as the EU and US.

Turkish attack on Afrin, northern Syria – in pictures Show all 9 1 /9 Turkish attack on Afrin, northern Syria – in pictures Turkish attack on Afrin, northern Syria – in pictures Smoke billows following a Turkish airstrike on a village in the Afrin district, on 28 January, 2018. Turkey launched operation "Olive Branch" on January 20 against the Kurdish People's Protection Units (YPG) militia in Afrin, supporting Syrian opposition fighters with ground troops and air strikes AFP Turkish attack on Afrin, northern Syria – in pictures Smoke billows from surrounding villages during the Turkish military operation against the Kurdish enclave on 28 January, 2018 AFP/Getty Turkish attack on Afrin, northern Syria – in pictures Twenty-year old Kifah al-Moussa, a Syrian Arab woman living among the Kurds of Afrin province, was working on a chicken farm in the village of Maryameen when a Turkish aircraft bombed the building at midday on 21 January, wounding her in the chest. When she recovered consciousness, she found eight people from one family lying dead around her Yara Ismail Turkish attack on Afrin, northern Syria – in pictures Mohamed Hussein, a 58-year-old Kurdish farmer, lies in the Afrin hospital, wounded in the head and eye after his home was bombed by Turkish aircraft on the second night of the attack Yara Ismail Turkish attack on Afrin, northern Syria – in pictures Syrian Kurds sit on benches overlooking a street in Afrin, on 28 January, 2018. Above is a memorial to ‘martyrs’ who died in the fight against Isis AFP/Getty Turkish attack on Afrin, northern Syria – in pictures Smoke is seen rising on the Syrian side of the border, at Hassa, near Hatay, southern Turkey as Turkish jet fighters hit People's Protection Unit (YPG) positions, on 28 January, 2018 AFP/Getty Turkish attack on Afrin, northern Syria – in pictures A Turkish made T-155 Firtina (Storm) howitzer is dispatched to the border at Hassa near Hatay, southern Turkey, on 28 January, 2018 AFP/Getty Turkish attack on Afrin, northern Syria – in pictures A Turkish soldier waves a flag on Mount Barsaya, northeast of Afrin, on 28 January, 2018 Reuters Turkish attack on Afrin, northern Syria – in pictures Turkey-backed Free Syrian Army fighters are seen in Barsaya mountain, northeast of Afrin, on 28 January, 2018 Reuters

The air and ground offensive launched in January opened a new front in Syria’s complicated conflict which has already killed at least 200 civilians in air strikes, shelling and sniper fire. Some 30,000 people have been displaced by the fighting.

Rights groups have condemned the Turkish operation as causing “unlawful” civilian deaths by failing to take necessary precautions before carrying out air strikes. The Turkish Defence Minister, Nurettin Canikli, has previously dismissed reports of harmed civilians as false.

The YPG and broader Arab-Kurdish coalition Syrian Democratic Forces (SDF) are supported by the West as the most effective ground force against Isis. In January the US pledged continued support for the YPG and SDF to ensure the jihadi militants do not form a resurgent movement – a strategy which enraged Turkey and contributed to the decision to launch the Afrin offensive.

Turkish President Recep Tayyip Erdogan has threatened his troops could reach Manbij in the northeast, a move which could potentially put the US and Turkey, Nato allies, on opposites sides of the front lines.

The Syrian government has sided with the YPG against Turkey. Ankara has said it has no intention of handing over control of Afrin to the regime once it has driven out Kurdish forces.

While the UN demanded a nationwide 30 day ceasefire on 25 February to calm the fighting between the government and rebels, Mr Erdogan has repeatedly said the resolution does not apply to his anti-terror operation.

A draft resolution from the EU on Thursday demanded Turkey halt the assault on Afrin.

"The European Parliament is apparently going to ask for the Afrin operation to be stopped," Mr Erdogan told supporters in Ankara.