Kurdish militia mounted a desperate defence Friday of a Syrian border town as neighbouring Turkey vowed to do its utmost to stop the strategic prize falling to the Islamic State group.
Shells rained down on the besieged town of Kobane, a day after the Turkish government won authorisation from parliament to take military action against the jihadists in both Syria and Iraq.
"We will do whatever we can so that Kobane does not fall," Turkish Prime Minister Ahmet Davutoglu said.
"We opened our arms to our brothers from Kobane," he added, recalling that his country had already given refuge to 160,000 civilians fleeing the area.
Ankara has not said what action it might take to prevent IS fighters from taking the town, and with it unbroken control of a long stretch of Turkey's more than 900 kilometre (560 mile) border with Syria.
An AFP correspondent on the frontier saw huge plumes of smoke above Kobane on Friday as the town's outnumbered and outgunned defenders came under intense mortar fire from jihadist positions less than two kilometres (little more than a mile) away.
At least 25 mortar rounds rained down on Kobane during Friday morning as Kurdish fighters battled IS armour on its outskirts, the Syrian Observatory for Human Rights said.
The militiamen destroyed two IS armoured vehicles southeast of the town, killing seven jihadists, said the Britain-based watchdog, which has a wide range of sources inside Syria.
Even though the vote by Turkish MPs does not commit the government to military action, it was swiftly welcomed by Washington.
The United States has been working to build a broad international alliance against the jihadists who have declared an Islamic "caliphate" straddling swathes of Iraq and Syria where they have committed widespread atrocities.
The US-led air campaign against IS in neighbouring Iraq received a boost on Friday with a decision by Australia to join combat sorties in support of Kurdish forces and the beleaguered Iraqi army.
In Kobane, a Syrian Kurdish official said Kurdish fighters had also destroyed an IS tank, but pleaded for more international support.
"For about 16 days we are defending Kobane. We are alone," Idris Nahsen told AFP by telephone.
"We need help from the international community. We need weapons and ammunition," he said.
US-led raids in Syria on Thursday destroyed an IS checkpoint near Kobane, the Pentagon said.
Turkish officials have cautioned against expecting rapid military steps by them following parliament's authorisation, and it remains uncertain if Turkish armed forces will be used against the militants.
The lack of action has angered and disappointed many in Turkey's own large Kurdish minority who have watched the jihadist onslaught on their fellow Kurds with mounting horror.
The United States is pressing Ankara for the use of the Incirlik air base in southern Turkey by US jets launching assaults on IS in Syria.
But it is unclear if Turkey will allow the transit of lethal weaponry and it may restrict the authorisation to humanitarian aid and non-lethal supplies.
Australia's decision to join the United States and five European countries in flying combat missions over Iraq came as the coalition stepped up its air campaign.
Australian Prime Minister Tony Abbott said the cabinet had also authorised the deployment of special forces to advise and assist Iraqi forces alongside British, Canadian and US advisers already on the ground.
The special forces were "not envisaged" to become directly involved in combat missions but would be "helping Iraqi forces with the planning and coordination of operations", Abbott stressed.
Some 1,600 US soldiers have been deployed to support Iraqi forces with equipment, training and information, while Canada said last month it had sent dozens of special forces soldiers to advise Iraqi personnel.
Retired US general John Allen, who is leading the international effort against IS, arrived in Iraq on Thursday for talks on boosting the campaign, the State Department said.
Britain was sending two more fighter jets to Cyprus on Friday, raising to eight the number it has deployed to the air campaign in Iraq.
The announcement was made by Prime Minister David Cameron during a visit to Britain's Akrotiri air base on the Mediterranean island.
It follows France's decision to raise to nine the number of jets it is committing to the air war in Iraq.