Kurdish fighters in the battleground Syrian town of Kobane weathered an onslaught by Islamic State group militants on Tuesday as they awaited promised reinforcements.
The Kurdish militia faced a fierce attack by IS fighters, including suicide bombers, late on Monday, that appeared aimed at cutting off the border with Turkey before any reinforcements could arrive, the Syrian Observatory for Human Rights said.
Fighting continued on Tuesday with exchanges between IS forces in the east of the town and Kurds in the west and there were reports of an explosion, probably a car bomb, the Britain-based monitoring group said.
Kobane has become a crucial symbolic battleground in the war against IS, which is fighting to extend areas under its control in Iraq and Syria where it has declared an Islamic "caliphate".
Ankara announced on Monday that it would help Kurdish forces from Iraq to relieve Kobane's beleaguered defenders, in a major shift of policy that was swiftly welcomed by Washington.
Iraqi Kurdish officials have said they will provide the training, although any forces sent will be Syrian Kurds.
The US administration has stepped up its commitment to Kobane in recent days, with Secretary of State John Kerry saying it would be "irresponsible" and "morally very difficult" not to help.
Three C-130 cargo aircraft carried out what the US military called "multiple" successful drops of supplies early on Monday, including arms provided by Kurdish authorities in Iraq.
One of the 27 bundles dropped went astray and US warplanes bombed it to prevent it falling into IS hands.
A US-led coalition has carried out more than 135 air strikes against IS targets around Kobane, but it was the first time it had delivered arms to the town's defenders.
Coalition aircraft carried out further strikes during the night, said the Observatory, which has a wide network of sources inside Syria.
IS lost at least five of its militants to air strikes on Monday and a further 12 in ground fighting, including two suicide bombers, the monitoring group said.
Five Kurdish fighters were also killed.
A senior US administration official said Monday's airdrop was in recognition of the "impressive" resistance put up by the Kurds and the losses they were inflicting on IS.
But US commanders said the top priority remains Iraq, where IS swept through much of the Sunni Arab heartland north and west of Baghdad in June, and both government and Kurdish forces are under pressure.
The jihadists attacked the Kurdish-controlled town of Qara Tapah on Monday, killing at least 10 people and prompting half of its population of 9,000 to flee.
"We are afraid IS will encircle us and turn this town into a second Amerli," said one resident of the town.
He was referring to a mainly Shiite Turkmen town further north which was besieged by IS for two months before government troops backed by militia broke through in late August.
Since last week, the Iraqi capital has seen a rise in the number of bomb attacks, several of which have been claimed by IS.
On Monday, a suicide bomber detonated explosives outside a Shiite mosque in the central Baghdad neighbourhood of Sinak, killing at least 11 people.
The violence has raised fears IS will attack large gatherings of Shiite worshippers during the upcoming Ashura commemorations, the target of devastating bombings in past years.
Iraqi Prime Minister Haidar al-Abadi was in Tehran on Tuesday for talks with his Shiite ally on the fight against IS.
The jihadists hold towns just a few miles (kilometres) from the Iranian border, and Tehran has been a key backer of Baghdad's efforts to hold them back.
According to a senior Iraqi Kurdish official, Iran has deployed troops on the Iraqi side of the border in the Khanaqin area northeast of Baghdad.
Iranian forces also played a role in breaking the siege of Amerli, another senior Kurdish official said.
But Abadi on Monday ruled out any foreign ground intervention to assist government forces in retaking territory lost to jihadists.
"No ground forces from any superpower, international coalition or regional power will fight here," Abadi told reporters.
"This is my decision, it is the decision of the Iraqi government, he said.
Syrian government forces are also battling the jihadists and on Tuesday advanced into the eastern city of Deir Ezzor's Hay Sina industrial zone in fighting that left three IS foreign fighters and seven soldiers dead.
But any cooperation with the government of President Bashar al-Assad is anathema for the US-led coalition, which has supported the opposition in the country's devastating three and a half year civil war.