Islamic State forces attacked the Kurdish border town of Kobani from three sides on Sunday, looking for a decisive blow against the out-gunned defenders.

Reuters:

"We had the most intense clashes of days, perhaps a week last night. (Islamic State) attacked from three different sides including the municipality building side and the market place," said Abdulrahman Gok, a journalist in Kobani.

"Clashes did not stop until the morning. We have had an early morning walk inside the city and have seen lots of damaged cars on the streets and unexploded mortar shells," he said.

CAR BOMBS

The Observatory reported two Islamic State car bombs hit Kurdish positions on Saturday evening leading to casualties. A cloud of black smoke towered over Kobani on Sunday.

A fighter from the female units of the main Syrian Kurdish militia in Kobani, YPG, said Kurdish fighters were able to detonate the car bombs before they reached their targets.

"Last night there were clashes all across Kobani ... this morning the clashes are still ongoing," she said, speaking on condition of anonymity.

The Observatory said 70 Islamic State fighters had been killed in the past two days, according to sources at the hospital in the nearby town of Tel Abyab, where Islamic State bodies are taken. Reuters cannot independently confirm the reports due to security restrictions.

The Observatory said some Syrian Arab fighters from the Revolutionaries of Raqqa Brigade, which are fighting alongside Kurdish fighters, had executed two Islamic State captives.

"One was a child of around 15 years old. They shot them in the head," he said.

Islamic State have also used executions throughout their campaigns in Syria and Iraq, killing hundreds of their enemies and civilians who are opposed to their cause, according to Islamic State videos and statements.

Hundreds of thousands have fled their advance. Turkey hosts about 1.5 million Syrian refugees, including almost 200,000 Syrian Kurds from Kobani.

Ankara has refused to rearm beleaguered Kurdish fighters, who complain they are at huge disadvantage in the face of Islamic State's weaponry, many of it seized from the Iraqi military when it took the city of Mosul in June.

Turkey views the YPG with suspicion for its long-standing links with the Kurdistan Workers Party (PKK), which has waged a 30-year armed campaign for self-rule in Turkey.

IS fighters are nothing if not relentless. Their efforts show just how important a propaganda victory would be for them if they could overrun Kobani. They would have stood up to coalition air power and overcome adversity, maintaining their aura of invincibility. On the other side of the ledger, President Obama's policy would be exposed as the hollow thing it is.

The Kurds will sell their lives dearly in protecting their city, but superior numbers and firepower is on the side of Islamic State. Whether that will be enough remains to be seen.