The Islamic State group was taking heavy losses in the Syrian battleground of Kobane Sunday as Iraqi forces fought the jihadists buoyed by US backing for top government security appointments.
US 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.
But US-led warplanes kept up their strikes on the jihadists around Kobane on Syria's northern border with Turkey, helping the town's Kurdish defenders to repulse a new attempt to cut their supply lines.
The Kurdish fighters, who have been under IS assault for more than a month, 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 their effort to seal the battle for the town, which has become a key prize as it is being fought under the gaze of the world's press massed just over the border in Turkey.
From Saturday into Sunday morning, a total of 31 jihadists died in the battle, the Syrian Observatory for Human Rights said.
Coalition air strikes killed 15, while another 16 died in the ground fighting, including two suicide bombers.
The Kurdish lost seven fighters, said the Britain-based Observatory, which has a wide network of sources inside Syria.
On Friday, IS lost 35 of its fighters while the Kurds lost three.
Medics and witnesses reported a steady flow of bodies from the Kobane fighting arriving at an IS-controlled hospital further east, the Observatory said.
The bodies of at least 70 IS fighters had been brought into the mortuary in the town of Tal Abyad over the past four days, they said.
The US military has said it sees "encouraging" signs in the battle for Kobane, although it warns the town may still fall.
But commanders have said repeatedly that the main priority remains the battle against IS in neighbouring Iraq, where the jihadists swept through much of the Sunni Arab heartland north and west of Baghdad in June.
The minority community's grievances 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 capable of mounting 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, the US top diplomat said. "So we're very pleased."
With Washington voicing approval, Prime Minister Haidar al-Abadi's office announced that he is to head to Tehran on Monday to discuss the fightback with his other key ally.
Washington has acknowledged that Tehran has an important role to play in the battle against IS, although it has kept the main Shiite power out of the coalition it has forged against the jihadists for fear of alienating Sunnis.
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.
Although it has not been part of the US-led coalition, Tehran has been a key backer of Abadi's government in its efforts to hold back the jihadist advance.
According to a senior Iraqi Kurdish official, it has deployed troops on the Iraqi side of the border in the Khanaqin area northeast of Baghdad.
Iranian forces also played a role in the Shiite Turkmen town of Amerli, where security forces and allied militiamen broke a months-long jihadist siege at the end of August, another senior Kurdish official has said.
Evidence also indicates that Iran sent Sukhoi Su-25 ground attack jets to Iraq, though it is unclear who subsequently piloted the aircraft.
The US-led coalition is carrying out air strikes against IS in Iraq as well as neighbouring Syria. It has also deployed military advisers.