Kurdish demonstrators stage a protest in the hall of the Parliament building in The Hague, waving flags with a portrait of jailed leader of Turkey's outlawed Kurdistan Workers Party (PKK), Abdullah Ocalan, on Monday. The demonstrators were protesting against the Islamic State and the siege of the Syrian town of Kobani.

Reuters/AFP/Mursitpinar, Turkey/Beirut

Islamic State fighters advanced into the southwest of the Syrian Kurdish town of Kobani overnight, a monitoring group said on Tuesday, taking several buildings to gain attacking positions from two sides of the city.

Two Islamic State flags were still visible over the eastern side of Kobani, Reuters journalists viewing from across the nearby Turkish border said. 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 (PYD) said on Monday,

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 led air strikes aimed at halting its progress.

The group wants to take Kobani to consolidate a dramatic sweep across northern Iraq and Syria, in the name of an absolutist version of Sunni Islam, that has sent shockwaves through the Middle East.

"There were clashes overnight. Not heavy but ISIS is going forward from the southwest. They have crossed into Kobani and control some buildings in the city there," said Rami Abdulrahman, head of the Syrian Observatory for Human Rights, using a former name for Islamic State.

"They are about 50 metres inside the southwest of the city."

Kobani activist Mustafa Ebdi confirmed the strikes, but said they had little effect.

“The strikes hit the Mishtenur area,” he said, referring to a plateau south of Kobani.

“But they (IS) aren’t gathered there. There are other places they should be hitting,” he said.

Ebdi confirmed street battles were being fought in the east, west and south of the town, which is bordered to the north by the Turkish border.

“The Kurdish fighters are still optimistic, they only have light weapons, but they know Kobani well,” he said.

“And they are fighting to defend their town and they say they will fight to the last person.”

The Observatory said that at least 34 IS jihadists and 16 Kurdish fighters had been killed in Kobani in the fighting on Monday.

Before the offensive, Kobani, known as Ayn al-Arab in Arabic, was home to refugees from the civil war which pits rebels against President Bashar al-Assad and has deteriorated into hundreds of localised battles between different factions.

An estimated 180,000 people have fled into Turkey from the Kobani region following the Islamic State advance.

The most powerful of the myriad militias fighting against 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 which has clashed with it in the past, pledging allegiance to its leader Abu Bakr al-Baghdadi, SITE monitoring service said on Monday.