Kurdish authorities in northeastern Syria on Thursday called for a humanitarian corridor to evacuate civilians from a flashpoint border town encircled by Ankara's forces, as Turkey's offensive entered its ninth day.
Turkish troops and their Syrian proxies have fully encircled Ras al-Ain, a key border town where Kurdish fighters have been putting up stiff resistance.
"It is the first real advance of the Turkish forces inside the city, following fierce resistance by the Syrian Democratic Forces (SDF)," the Britain-based Syrian Observatory for Human Rights (SOHR) said.
Massively outgunned by the Turkish army and its airforce, the Kurdish administration pleaded to allow civilians to exit the town that Turkey aims to capture.
It called for "urgent intervention to open a safe humanitarian corridor to evacuate dead and wounded civilians trapped in Ras al-Ain".
Ankara's Syrian proxies -- mostly Arab and Turkmen former rebels they use as a ground force -- hit a hospital in the town on Thursday, trapping patients and staff inside, the Observatory said.
The monitor said the extent of damage in the facility was not yet clear.
The attack came as violent clashes raged inside the town, according to the Observatory and Syrian rebel fighters.
"The battles are at their most intense," said Abu Imran al-Homsi, a rebel commander fighting alongside Ankara's forces.
"We have surrounded (Ras al-Ain) from all sides and cut off supply lines," another rebel commander told AFP.
Observatory head Rami Abdul Rahman said that Ankara's forces had taken about half of the town by Thursday morning.
"There have been intensive air strikes on Ras al-Ain over the past three days," he said.
Kurdish-led SDF forces quickly lost a long stretch of border when Turkey launched its assault on October 9.
They organised a defence of Ras al-Ain, however, with a network of tunnels, berms and trenches that held off Turkish forces and their proxies for about a week.
An AFP correspondent on the Turkish side of the Ras al-Ain front line said there was constant gunfire and blasts from artillery and air strikes.
Turkey aims to create a 30-kilometre-deep (20-mile) buffer on the Syrian side of the border to keep Kurdish militias at bay and set up a resettlement zone for some of the 3.6 million Syrian refugees living on its soil.
Turkish President Recep Tayyip Erdogan has so far ignored international pressure to halt the offensive, which the Observatory says has left dozens of civilians dead and displaced more than 300,000 people.