The ISIS has detonated two bridges under their control in the northern Tal Abyad district of Syria's Raqqah province, according to the Syrian Observatory for Human Rights (SOHR).
The Observatory reported that ISIS destroyed the two villages of al-Jlab and Shrei’an in southeast and southwest Tal Abyad in an attempt to prevent the Kurdish People's Protection Units (YPG) from advancing further towards the area.
The SOHR said the clashes between ISIS fighters and the YPG, which is backed by US-led coalition air strikes, are still taking place on the eastern outskirts and southwest of the city of Tal Abyad as the YPG succeeded in seizing several villages.
Reliable sources told the SOHR that YPG fighters could advance again southeast of the city of Tal Abyad on the road to the town of Suluk and seize more villages. They are now 5 kilometres away from the city of Tal Abyad, close to the Turkish border.
“At least 150 IS militants are still inside the city of Tal Abyad and threatening to retreat from the city if military reinforcement does not reach them,” the SOHR said.
ISIS "pulled back on Sunday from the town of Suluk in the northern Raqqa countryside after it was besieged for 48 hours by the YPG."
The SOHR also said that the YPG controls wide areas of Tal Tamir, another key town on the same front line in Syria's Hasakah province, in which fierce confrontations took place on Wednesday.
ISIS is said to be planning to seize the town of Tal Tamir in Hasaka province, as well as Ras al Ayn, located just 5 kilometres away from Tal Abyad. This would give them control over key routes that link to their bastion city of Mosul in Iraq.
According to the SOHR, coalition air raids in support of the YPG were carried out against ISIS as the group advanced in the area. Clashes between ISIS and the YPG in Suluk and other countryside areas near Tal Abyad also continued, accompanied with heavy aerial bombardment by coalition warplanes, forcing residents to head towards the city of Raqqa.
Coalition warplanes also hit a settlement unit in Tal Abyad in the northern Raqqa province, killing 20 civilians, the Syrian Revolution General Commission (SRGC) said in a statement on Saturday.
Tal Abyad, held by ISIS, is an oil-rich city located 65 kilometres east of the key Kurdish border town of Kobane, and ISIS' de facto capital in Syria's Raqqa province.
The YPG has been fighting against ISIS for control of the city since the Kurds launched an offensive earlier this month, advancing within five kilometres of Tal Abyad on Saturday.
Rami Abdel Rahman, the head of the SOHR, said on Sunday that ‘’Kurdish forces are on the eastern outskirts of Tal Abyad, only five kilometres [three miles] from the town.’’
The YPG is the military wing of the PYD. The PYD is seen as the Syrian affiliate of the outlawed PKK. Both separatist groups aspire to create an independent nation out of parts of Syria, Iraq, Turkey and Iran. The PKK is recognised as a terrorist organisation by the US, EU and Turkey, whereas the PYD has managed to remain off global terror lists.
According to UN estimates over 220,000 people have been killed in Syria since the start of the uprising against the government that later descended into a complex civil war. More than 6.7 million people have fled the country while millions of others are displaced internally.