The Islamic State group took heavy losses Sunday in the Syrian battleground of Kobane as Iraqi forces fought the jihadists buoyed by US backing for top government security appointments.
Secretary of State John Kerry said the appointment of defence and interior ministers after weeks of delay was a "very positive step forward" in the fightback against IS in Iraq, which Washington has made its priority.
American-led warplanes launched 11 air strikes near Kobane on Saturday and Sunday, US Central Command said, helping Kurdish fighters repulse a new IS attempt to cut their supply lines from Turkey.
Kobane's Kurdish defenders have been under IS assault for more than a month. They weathered fierce street fighting and at least two jihadist suicide bombings but the front line remained unchanged on Sunday, a Kurdish official said.
"(IS) brought in reinforcements... and attacked hard," Idris Nassen told AFP by telephone. "But thanks to air strikes and (the Kurdish fighters') response, they did not make any progress."
The IS fighters suffered heavy losses in Kobane, which has become a key prize as it is being fought under the gaze of the world media massed just across the border in Turkey.
From Saturday into Sunday morning, 31 jihadists died in the battle, said the Syrian Observatory for Human Rights.
Coalition air strikes near Kobane hit 20 IS fighting positions, five IS vehicles and two IS-held buildings, said Central Command.
The Observatory, which has a network of sources inside Syria, said 15 jihadists were killed in the air strikes while 16 others died in ground clashes along with seven Kurdish fighters.
- Hospital counts IS bodies -
With the fighting raging, the corpses of at least 70 jihadists were brought over the past four days into an IS-controlled mortuary in the town of Tal Abyad further east, said the Observatory.
The US military has said it sees "encouraging" signs in the battle for Kobane, but has warned the town may still fall.
On Sunday the White House said President Barack Obama called his Turkish counterpart Recep Tayyip Erdogan and they pledged to "strengthen cooperation" against IS in Syria.
Signup to our newsletter and follow us on Facebook and Twitter!
But US commanders say their top priority remains neighbouring Iraq, where IS swept through much of the Sunni Arab heartland north and west of Baghdad in June.
Grievances of the Sunni majority against the Shiite led-government were a major factor in the lightning advance, and Washington has been piling pressure on Baghdad to form an inclusive government to mount a fightback.
On Saturday, the remaining posts in a new government line-up were finally approved by parliament, including a Sunni as defence minister and a Shiite as interior minister.
"These were critical positions to be filled, in order to assist with the organising effort" against IS, Kerry said. "So we're very pleased."
- Iran-Iraq talks -
With Washington voicing approval, Prime Minister Haidar al-Abadi's office announced he would visit Iran on Monday to discuss the fightback with Iraq's other key ally.
The US has kept Iran out of the coalition for fear of alienating Sunnis but acknowledges Tehran has an important role to play in the battle against IS.
Abadi's talks in Iran are part of his bid "to unite the efforts of the region and the world to help Iraq in its war against the terrorist group," his office said.
Tehran is a key backer of Abadi's government in its efforts to hold back the advance of the Sunni extremist IS.
Kurdish officials say Iran has deployed troops on the Iraqi side of the border in the Khanaqin area northeast of Baghdad and played a role in Amerli, a Shiite Turkmen town where security forces and allied militiamen broke a months-long jihadist siege in August.
Evidence also indicates that Iran sent Sukhoi Su-25 ground attack jets to Iraq, though it is unclear who subsequently piloted the aircraft.
As well as Syria, the US-led coalition is carrying out air strikes against IS in Iraq, including 10 on Saturday and Sunday. It has also deployed military advisers.
On Sunday a suicide bomber detonated explosives at a Shiite mosque in Baghdad, killing at least 18 people and wounding 30.
It came as Australian Foreign Minister Julie Bishop said in Baghdad that she had reached a deal to deploy about 200 special forces in Iraq to assist in the fight against the jihadists.