The Turkish army has been bombing Kobane’s Kor Eli and Selim villages with heavy weapons, as the president, Recep Tayyip Erdogan, promised to expand Turkey’s military border operations against the Kurdish People’s Protection Units (YPG) that has been the key actor in the war on Islamic State.

The raids came on the heels of a week of threats by Turkey, promising to clear the YPG from Manbij, east of Euphrates river and its surrounding countryside.

The Kurdish-led Syrian Democratic Forces (SDF) said the Turkish attacks had led to a temporary halt in the U.S.-backed campaign it is waging against Islamic State (IS) near the Iraqi border.

Turkey has repeatedly warned it would launch a cross-border offensive against the Kurdish YPG militia east of the Euphrates River in Syria, if the U.S. military which supports the Kurdish fighters does not ensure their withdrawal.

Turkish state broadcaster TRT said barrages of howitzer shells were launched at the Ayn al-Arab, or Kobani region, from Turkey's southeastern province of Sanliurfa, along the Syrian border. Four militants were killed and six wounded in the strikes on the region.

The SDF, in a statement, said Turkish forces were attacking its positions along the length of the border. SDF forces had responded by destroying a Turkish military vehicle, it said, without giving the location. The SDF reserved the "right to respond to all kinds of attacks."

In 2014, when Islamic State encircled the city of Kobane, Kurdish forces fought street by street, house by house for 4 months.

Following the developments, Erdogan once confidently said: "Kobane has almost fallen." He always preferred Islamic State controlling the Syrian-Turkish border rather than Kurdish forces controlling it.

And Erdogan was "almost" right. Despite Kurdish resistance, IS break through into Kobane in early October and take districts in the east and south of the town. Their black flag can be seen from inside Turkey, where the Turkish Army only stood and watched.

The US-led coalition stepped up strikes on militants in the town, and a series of counter-offensives by Kurdish fighters took back important positions of the city. From then on, Kurdish fighters continued to steadily push back the IS advance over the coming weeks.