Turkish President Recep Tayyip Erdogan has said the Syrian border town of Kobane is "about to fall" to Islamic State militants.
Mr Erdogan said that a ground operation is needed to defeat the militant group, which has taken key positions in the town.
His comments came after the latest air strikes by the US-led coalition, which were aimed at stopping the IS advance.
The extremists pushed into Kobane yesterday, seizing three districts in the city's east after fierce street battles with its Kurdish defenders.
Up to 400 people have been killed in the fighting, which has spread to new areas in the south and west, a monitoring group said.
However, with Kurdish People's Protection Unit fighters seeking to halt the IS advance, a Kurdish flag could still be seen flying from a roof in the centre of the town.
Two Islamic State flags were still visible over the eastern side of Kobane. Sporadic gunfire could be heard.
More than 2,000 Syrian Kurds including women and children were evacuated from the town, a member of the Kurdish Democratic Union Party said yesterday.
The al-Qaeda offshoot has ramped up its offensive in recent days against the mainly Kurdish border town, despite being targeted by US-led coalition air strikes.
The group wants to take Kobane to consolidate a dramatic sweep across northern Iraq and Syria, in the name of an absolutist version of Sunni Islam.
The move has sent shockwaves through the Middle East.
"There were clashes overnight. Not heavy but ISIS is going forward from the southwest," said Rami Abdulrahman, head of the Syrian Observatory for Human Rights, using a former name for the self-proclaimed Islamic State.
"They have crossed into Kobane and control some buildings in the city there. They are about 50 metres inside the southwest of the city."
A strong Turkish force is monitoring the fighting from across the border.
Before the offensive, Kobane, known as Ayn al-Arab in Arabic, was home to refugees from the Syrian civil war.
An estimated 180,000 people have fled into Turkey from the Kobane region following the Islamic State advance.
The most powerful of the myriad militias fighting against President Bashar al-Assad, Islamic State has boosted its forces with foreign fighters and defectors from other rebel groups.
It gained additional heavy weaponry after its fighters swept through northern Iraq in June, seizing arms from the fleeing Iraqi army.
The group released a video showing dozens of men said to be from Ahrar al-Sham, a rival Islamist group that has clashed with it in the past, pledging allegiance to its leader Abu Bakr al-Baghdadi.
Meanwhile, four people have died and many others were wounded in southeast Turkey today local media reported.
It came after violent clashes erupted between police and Kurds demonstrating in support of the Syrian Kurdish border town of Kobani.
Two people died in the southeastern province of Siirt while one was killed in neighbouring Batman.
Earlier, a 25-year-old man died in the eastern city of Mus, as thousands of Kurdish protesters demanded the government do more to protect Kobani.
Elsewhere, dozens of Kurdish demonstrators burst into the European Parliament in Brussels today, to protest the Islamic State group's attack on the town of Kobane.
Brandishing Kurdish flags and effigies of their jailed separatist leader Abdullah Ocalan, the men and women broke through a police barrier to enter the hall of the building.
They staged a sit-in while several European members of parliament came to meet with them.
"We will fight Islamic State," the head of the socialist group in parliament, Gianni Pittella, told the protesters, drawing applause.
