The black flag of Isis has been raised in the Syrian town of Kobani as the battle between the Islamist militants and Kurdish forces rages on the border with Europe.

While the Kurds remain in control of the town, two black banners with Arabic writing have been spotted at its eastern entrance, one raised over a building and another on a nearby hill.

Kobani and the surrounding area has been under attack since mid-September, with Islamic State militants capturing dozens of nearby Kurdish villages.

Some 160,000 Syrians have been forced to flee while Kurdish forces have struggled to push back the jihadists despite being aided by the US-led coalition airstrikes.

The British-based Syrian Observatory for Human Rights and a statement from the Kurdish force known as the People's Protection Units, or YPK, said more than 45 fighters on both sides were killed Sunday near Kobani, including a Kurdish female fighter who blew herself up, killing several jihadists.

A picture taken from Turkey shows an Islamic State (IS) flag displayed by militants in the east of Syrian Kobani city, at the Syria-Turkey border near Sanliurfa (EPA)

On the Turkish side of the border, at least 14 Turkish army tanks took up positions on a hilltop near Kobani. Heavy bombardment could be heard down below as plumes of smoke rose from the town.

A house and a small grocery store in Turkey were both struck by a shell from the fighting, but no one was wounded. At least four people were injured in a similar incident on Sunday.

The YPK said in a statement that there were 50 points of clashes around Kobani on Sunday, adding that 74 Islamic State fighters as well as 15 Kurdish gunmen were killed.

The Observatory, which gathers information from activists inside Syria, said 27 jihadists and 19 Kurds were killed in the battles, making it one of the deadliest days since the latest round of fighting began three weeks ago.

Syrian Kurdish forces have long been among the most effective adversaries of the Isis (also known as Islamic State and Isil), keeping it out of their enclave in northeastern Syria even as the extremists routed the armed forces of both Syria and neighbouring Iraq in recent months.

But in recent weeks the overstretched Kurds have struggled to counter the increasingly well-armed jihadists.

Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Show all 22 1 /22 Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Mourners gathered to bury three Kurdish fighters from Kobani Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border An explosion rocks the Syrian city of Kobani during a reported suicide car bomb attack by Isis Getty Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border The US and Turkey have stepped up support for Kurdish fighters defending Kobani against Isis but it is still feared the town may fall; above, observers watch the fighting from a nearby village AFP Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border People are silhouetted on the top of a hill close to the border line between Turkey and Syria near Mursitpinar bordergate as they watch the U.S led airstrikes over ther Syrian town of Kobani Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Syrian Kurd Kiymet Ergun (56) gestures, in Mursitpinar on the outskirts of Suruc, at the Turkey-Syria border, as thick smoke rises following an airstrike by the US-led coalition in Kobani, as fighting continued between Syrian Kurds and the militants of Isis group Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Kurdish Rabia Ali (R) accompanied by her son Ali Mehmud (L) mourn at the grave of her son Seydo Mehmud 'Curo', a Kurdish fighter, who was killed in the fighting with the militants of the Islamic State group in Kobani, and was buried at a cemetery in Suruc, on the Turkey-Syria border Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Mourners gather for the funeral of two Syrian Kurdish fighters killed in fighting with militants of the Isis group in Kobani at a cemetery in Suruc Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Kurdish refugees fleeing Kobani enter Turkey at Suruc Getty Images Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Smoke from air strikes against Isis in Kobani can be seen from across the border in Mursitpinar, Turkey Getty Images Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Newly arrived Kurdish refugees after crossing into Turkey from the Syrian border town of Kobani Getty Images Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Kurdish refugees cross the border near Kobani Getty Images Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Smoke rises from the city centre of Kobani Getty Images Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Isis militants stand next to an Isis flag atop a hill in the Syrian town of Ain al-Arab, known as Kobani by the Kurds, as seen from the Turkish-Syrian border, with Turkish troops in foreground, in the southeastern town of Suruc, Sanliurfa province Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border A flag of Isis group is seen atop of a building at the eastern side of the town of Kobani, Syria, where fighting had been intensified between Syrian Kurds and the militants of Isis group Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Militants with the Isis group are seen after placing their group's flag on a hilltop at the eastern side of the town of Kobani Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Smoke rises after an apparent airstrike by allied forces against Isis targets in the west of Kobani where Kurdish fighters try to defend the town, near Suruc district, Sanliurfa, Turkey Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Newly arrived Syrian Kurdish refugees stand at the back of a truck after crossing into Turkey from the Syrian border town Kobani, near the southeastern Turkish town of Suruc in Sanliurfa province Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Turkish forces fire tear gas to disperse Kurds on the outskirts of Suruc, at the Turkey-Syria border, as fighting intensified between Syrian Kurds and the militants of Isis in Kobani Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Kurdish men shout towards Turkish army soldiers, who try to evacuate people from the village of Mursitpinar, on the other side of the Syrian town of Ain al-Arab, known as Kobani by the Kurds, by the Turkish-Syrian border in Sanliurfa province Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Turkish Kurds walk as tanks in the background hold their positions on a hilltop in the outskirts of Suruc, at the Turkey-Syria border, overlooking Kobani in Syria where fighting had ben intensified between Syrian Kurds and the militants of Isis Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Turkish Gendarmerie use tear gas to disperse Kurdish protesters during a demonstration against the Isis, at the Syria-Turkey border near Sanliurfa Isis fighters in Kobani (2014): Civilians flee as militants enter Syria-Turkey border Syria-Turkey border Smoke rises from the Syrian town of Ain al-Arab, on the Turkish-Syrian border in the southeastern town of Suruc, Sanliurfa province

"They are using tanks, artillery and all kinds of weapons they captured in Iraq and Syria," said Nasser Haj Mansour, a defense official in Syria's Kurdish region, referring to the Isis, which has declared a caliphate in the large areas it controls in both countries.

The Observatory's director Rami Abdurrahman said Monday that one of the attacks against Isis the day earlier was carried out by a female Kurdish fighter who blew herself up, killing 10 jihadists.

The YPK statement identified the suicide attacker as Deilar Kanj Khamis, better known by her military name, Arin Mirkan.

Khamis was a member of a YPK branch known as the Women's Protection Units, or YPJ. The force has more than 10,000 female fighters who have played a major role in the battles against Isis, Haj Mansour said.

Haj Mansour said Kurdish fighters withdrew from a position on the strategic hill of Mashta Nour near Kobani. Khamis stayed behind, and as Isis fighters moved in she attacked them with gunfire and grenades, eventually blowing herself up. The Kurds then recaptured the position.

Turkish tanks hold their positions on a hilltop in the outskirts of Suruc, at the Turkey-Syria border, overlooking Kobani in Syria (AP)

"If necessary, all our female and male fighters will become Arin. The attacks by mercenaries of Daesh against Kobani will not be allowed to achieve their goals," the YPK statement said, using the Arabic acronym for the Islamic State group.

Nawaf Khalil, a spokesman for Syria's Kurdish Democratic Union Party, or PYD, said: "Yesterday was a very violent day but they were neither able to enter Kobani nor Mashta Nour."