Fighters from the Islamic State of Iraq and the Levant (ISIL) are closing in on a key Kurdish town in Syria, as neighbouring Turkey vowed to do its utmost to stop the strategic prize falling to the armed group.

Heavy fighting between ISIL and Kurdish militias was reported throughout Kobane on Friday with artillery shells landing on eastern and western neighbourhoods of the besieged town.

Al Jazeera's Bernard Smith, reporting from Suruc in southern Turkey, said intense fighting including shelling, gunfire and explosions could be heard from across the border.

Sources from the town told Al Jazeera that ISIL had seized control of hills around Kobane, and backed by military vehicles and tanks, launched an attack on a south-eastern suburb early in the morning.

At least 60 mortar rounds rained down on Kobane on Friday as Syrian Kurdish fighters, known as the Peoples Protection Units (YPG), battled ISIL on its outskirts, the Syrian Observatory for Human Rights monitoring group said.

The YPG reportedly destroyed two ISIL armoured vehicles southeast of the town, and killed seven ISIL fighters, the Britain-based Syrian Observatory said.

Intensified shelling in and around Kobane has angered Kurds on the Turkish side of the border, who have blamed the Turkish government for not doing enough to stop the assault.

Turkey's prime minister said on Thursday he would do whatever he could to prevent the fall of Kobane.

"We will do whatever we can so that Kobane does not fall," Ahmet Davutoglu said.

"We opened our arms to our brothers from Kobane."

Davutoglu pointed out that his country had already given refuge to 160,000 civilians fleeing the area.

On Thursday, Turkey's parliament authorised the government to carry out cross-border military operations in Iraq and Syria to fight ISIL and other armed groups.

Buy Al Jazeera's Smith said there was no indication Turkey was planning to send troops to the area so soon after parliament authorised troop deployment across the border.

Meanwhile, Syria's Foreign Ministry said on Friday that any Turkish intervention on its soil would be considered an act of "aggression".

"The international community and, in particular, the Security Council, should act to put an end to the adventures of the Turkish leadership, which represents a threat to world security and peace," the Foreign Ministry said in a statement.

The US has been working to build a broad international alliance against ISIL who have declared an Islamic "caliphate" straddling swathes of Iraq and Syria where they have committed widespread atrocities.

The US-led air campaign against the group's positions 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.