Kurdish forces defending a Syrian town near the Turkish border have clashed with Islamic State fighters after repelling a wide-ranging assault the day before.
More than 45 fighters on both sides were reportedly killed yesterday near the town of Kobani, including a Kurdish female fighter who blew herself up, killing several jihadists.
The information came from the Britain-based Syrian Observatory for Human Rights and a statement from the Kurdish force known as the People's Protection Units, or YPK.
Kobani and surrounding areas have been under attack since mid-September, with Islamic State militants capturing dozens of nearby Kurdish villages.
The assault has forced some 160,000 Syrians to flee and strained Kurdish forces, who have struggled to push back the jihadists despite being aided by US-led coalition airstrikes.
On the Turkey side of the border, at least 14 Turkish army tanks took up defensive positions on a hilltop near Kobani. Heavy bombardment could be heard down below as plumes of smoke rose from the town.
A shell from the fighting struck a house and a small grocery shop across the border in Turkey, but no one was wounded. At least four people were injured in a similar incident yesterday.
The YPK said there were 50 points of contact around Kobani yesterday, adding that 74 Islamic State fighters and 15 Kurdish gunmen were killed.
The Observatory 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 Islamic State group, keeping it out of their enclave in north-east Syria even as the extremists have routed the armed forces of Syria and Iraq in recent months.
But in recent weeks the overstretched Kurds have struggled to counter the jihadists, who have looted heavy arms and vehicles from captured Syrian and Iraqi army bases.
"They (Islamic State) are using tanks, artillery and all kinds of weapons they captured in Iraq and Syria," said Nasser Haj Mansour, a defence official in Syria's Kurdish region.
The Observatory's chief Rami Abdurrahman said one of the attacks against Islamic State 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 YPG. The force has more than 10,000 female fighters who have played a major role in the battles against the Islamic State group, Haj Mansour said.
He said Kurdish fighters withdrew from a position on the strategic hill of Mashta Nour near Kobani.
But Khamis stayed behind and as the Islamic State fighters moved in she attacked them with gunfire and grenades, eventually blowing herself up. The Kurds then recaptured the position.
"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 leading Kurdish Democratic Union Party, or PYD, said: "Yesterday was a very violent day but they were neither able to enter Kobani nor Mashta Nour."
Turkey, a Nato member, said the alliance has drawn up a strategy to defend the country if it is attacked along its border with Syria.
Defence Minister Ismet Yildiz said Nato did the planning at Turkey's request as Islamic State militants try to take Kobani.
He said: "If there is an attack, Nato's joint defence mechanism will be activated."
Two banners of the Islamic State group have been raised over a Kobani building and a nearby hill, suggesting the militants may have broken through the Kurdish perimeter.