Huge plumes of smoke were seen rising from Kobane as its outnumbered defenders came under intense fire from IS fighters who have advanced to its gates despite US-led air strikes against them.
At least 60 IS mortar rounds rained down on the town Friday, according to the Syrian Observatory for Human Rights, which described it as the heaviest bombardment since mid-September.
It said a Chechen member of the IS organisation was leading the assault on the town, which is considered a strategic prize.
"We will do whatever we can so that Kobane does not fall," Turkish Prime Minister Ahmet Davutoglu said, adding that about 186,000 people had flooded across the border from Syria in less than two weeks.
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He reaffirmed President Recep Tayyip Erdogan's call for a no-fly zone above northern Syria, saying that the Damascus regime could otherwise "carry out strikes on the Aleppo region with all its might and send three million refugees into Anatolia."
Damascus was quick to counter, saying the Turkish stance "represents a real aggression against a member state of the United Nations."
The United States has been working to build a broad international alliance against the jihadists who have declared an Islamic "caliphate" straddling swathes of Iraq and Syria where they have committed widespread atrocities.
The Pentagon said aircraft from Saudi Arabia and the United Arab Emirates joined US warplanes in new bombing raids Friday against IS in Syria.
Coalition planes hit militant tanks, oil refineries and a training camp, it said.
With the coalition's air component expanding, Dutch Defence Minister Jeanine Hennis-Plasschaert said Friday her country could send F-16 fighter bombers into action over Iraq by this weekend.
And Canada's premier sought parliament's support for a plan -- which is expected to be approved -- to send fighter jets to help fight IS in Iraq.