Three civilians have been killed in shelling by fighters belonging to the Islamic State of Iraq and the Levant (ISIL) group  in the border town of Kobane, Al Jazeera has learned.

Several others were injured in the attack on Wednesday.

Kurdish forces have been struggling to defend the town from ISIL's offensive.

A US-led coalition on September 23 launched air strikes against ISIL positions in Syria, including around Kobane.

The Syrian Observatory for Human Rights, a British based organisation, said at least 865 people, 746 of them ISIL fighters, have been killed in the coalition attacks.

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Another 50 were civilians, including eight children, while 68 of those killed were members of Syria's al-Qaeda affiliate.

The US has said it takes reports of civilian casualties seriously and says it has a process to investigate each allegation.

The US-led coalition's aerial campaign in Syria began before dawn on September 23 in what President Barack Obama called an effort to roll back and ultimately destroy ISIL.

The group has been the primary target of the coalition's strikes, although on at least two occasions the US has targeted what it says is a specific cell within al-Nusra Front allegedly plotting attacks against American interests.

The air strikes in Syria expanded upon a US-led operation in neighbouring Iraq against ISIL, which has seized control of a large chunk of territory spanning the two countries.

The US justified its action in Syria under Article 51 of the UN charter, which covers an individual or collective right to self-defence against armed attack.

About 200,000 people have been killed in Syria's conflict, which is now in its fourth year, according to the UN.

Source: Al Jazeera and agencies