MURSITPINAR, Turkey -- Islamic State fighters backed by tanks and artillery pushed into an embattled Syrian town on the border with Turkey on Monday, touching off heavy street battles with the town's Kurdish defenders.
Hours after the militants raised two of their Islamic State group's black flags on the outskirts of Kobani, the militants punctured the Kurdish front lines and advanced into the town itself, the Local Coordination Committees activist collective and the Britain-based Syrian Observatory for Human Rights said.
"They're fighting inside the city. Hundreds of civilians have left," said Observatory director Rami Abdurrahman. "The Islamic State controls three neighbourhoods on the eastern side of Kobani. They are trying to enter the town from the southwest as well."
The centre of the town was still in Kurdish hands, Abdurrahman said. Kurdish officials could not be immediately reached for comment.
Since it began its offensive in mid-September, the Islamic State group has barrelled through one Kurdish village after another as it closed in on its main target -- the town of Kobani, also known as Ayn Arab. The assault has forced some 160,000 Syrians to flee and put a strain on Kurdish forces, who have struggled to hold off the extremists even with the aid of limited U.S.-led airstrikes.
Capturing Kobani would give the Islamic State group, which already rules a huge stretch of territory spanning the Syria-Iraq border, a direct link between its positions in the Syrian province of Aleppo and its stronghold of Raqqa, to the east. It would also crush a lingering pocket of resistance and give the group full control of a large stretch of the Turkish-Syrian border.
After initially setting up positions to the east, south and west of the town, the Islamic State group shelled Kobani for days to try to loosen up the defences. Just across the frontier in Turkey, the steady thud of artillery, sharp crackle of gunfire and plumes of smoke rising over the rooftops testified to the intensity of the fight all day Monday.
"ISIS is advancing further toward Kobani day by day," said Ismet Sheikh Hassan, the defence chief for Kurdish forces in the area, using an alternative name for the Islamic State group. "ISIS is fighting with tanks and heavy weapons and they are firing randomly at Kobani. There are many civilian casualties because of the shelling."
The Syrian Observatory for Human Rights said about 20 Islamic State fighters managed to sneak into the eastern part of Kobani overnight, but were ambushed and killed by Kurdish militiamen.
Syrian Kurdish forces have long been among the most effective adversaries of the Islamic State group, keeping the extremists out of the Kurdish enclave in northeastern Syria even as the militants routed the armed forces of both Syria and neighbouring Iraq.
But in recent weeks the overstretched Kurds have struggled to counter the increasingly well-armed militants, who have been strengthened by heavy weapons looted from captured Syrian and Iraqi military bases.
As fighting raged Monday within sight of the Turkish border, the country's defence minister said the NATO alliance had drawn up a strategy to defend Turkey, a NATO member, if it is attacked along its frontier with Syria. The NATO move came at Turkey's request, Defence Minister Ismet Yilmaz said.
Turkey has warily watched the fight for Kobani unfold. On Monday, at least 14 Turkish tanks took up defensive positions on a hilltop on Turkish soil near the beseiged town, while a shell from the fighting struck a house and a grocery store inside Turkey, but no one was wounded.
Monday's heavy clashes followed a particularly bloody Sunday, when more than 45 fighters on both sides were killed, according to the Observatory and a statement from the Kurdish force known as the People's Protection Units, or YPG.
The dead included a Kurdish female fighter who blew herself up, killing 10 jihadists,said Observatory director Rami Abdurrahman. A YPG statement identified the suicide attacker as Deilar Kanj Khamis, better known by her military name, Arin Mirkan.
Khamis was a member of the Women's Protection Units, a branch of the main Kurdish militia. The force has more than 10,000 female fighters who have played a major role in the battles against the Islamic State group, said Nasser Haj Mansour, a defence official in Syria's Kurdish region.
Haj Mansour said that after Kurdish fighters were forced Sunday to withdraw from a strategic hill south of Kobani, 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 (the Islamic State group) against Kobani will not be allowed to achieve their goals," the YPG statement said.
Syria's Kurds have been lobbying for greater support from the international community to help them in their fight against the Islamic State militants. While the U.S.-led coalition has carried out some airstrikes against militant positions around Kobani, those strikes have failed to blunt the extremists' advance.
U.N. Secretary-General Ban Ki-moon expressed "grave concern" about the ongoing offensive by Islamic State militants on Kobani, which is also known as Ayn al-Arab, according to a statement released by his spokesperson. In light of the "barbarous campaign" waged by the Islamic State group, Ban "urgently calls on all those with the means to do so to take immediate action to protect the beleaguered civilian population of Ayn al-Arab."
On a broader level, Syrian Kurds and the Kurdish Democratic Party, or PYD, have struggled to gain the sort of Western backing that their brethren in Iraq enjoy.
That stems, at least in part, from Turkey's wariness of the PYD, which Ankara believes is affiliated with the Kurdish PKK movement that has waged a long and bloody insurgency in southeast Turkey.
Over the weekend, Syrian Kurdish leader Saleh Muslim Mohammed visited Turkey, where he met with Turkish officials, said PYD spokesman Nawaf Khalil.
Turkish Deputy Prime Minister Bulent Arinc confirmed that Mohammed visited the Turkish capital, Ankara, but did not elaborate.
On Friday, Arinc said that Mohammed's group made mistakes in the past by siding with Syrian President Bashar Assad and by creating Kurdish cantons in Syria's north.
The PYD denies links to Assad's government, which withdrew troops from the predominantly Kurdish areas in northeastern Syria in 2012, allowing Kurdish forces to assume control and eventually declare their own civil administration.
On Monday, in the Kurdish-held city of Hassakeh in northeastern Syria, three bombings targeting security forces killed some 30 people, said PYD spokesman Khalil. The Observatory also reported the blasts and the same death toll, and said the attacks were carried out by the Islamic State group.
Lucas reported from Beirut. Associated Press writers Bassem Mroue in Beirut, Mehmet Guzel in Suruc, Turkey, and Suzan Fraser in Ankara contributed to this report.
