Turkish President Recep Tayyip Erdogan criticised as "wrong" the airdrops of ammunition and weapons by US jets to Kurdish fighters battling the Islamic State group in the Syrian town of Kobane.
He said the weapons had fallen into the hands of the Democratic Union Party (PYD) - a Syrian Kurdish group that Turkey does not support - and also IS fighters.
"It has become clear that this was wrong," he told reporters in Ankara.
Meanwhile, large explosions could be heard in Kobane today, hours after the Pentagon warned the town could still fall to IS militants.
IS militants have been battling Kurdish fighters for a month to take control of the town, but stepped-up air strikes by US-led forces have helped Kurds fend off the advance.
Asked about a plan for Turkey to facilitate the passage of Iraqi Kurdish peshmerga fighters to Kobane to help in its defence, Mr Erdogan said he proposed this move in a telephone call with US President Barack Obama at the weekend.
"I have difficulty understanding why Kobane is so strategic for them because there are no civilians there, just around 2,000 fighters," Mr Erdogan said.
"At first, they didn't say yes to peshmergas, but then they gave a partial yes and we said we would help."
He added that talks were continuing among officials on the details of the peshmergas' transit through Turkey.
One Turkish journalist close to the government said around 500 of them were expected to cross into Kobane this weekend.
The Pentagon said yesterday that the vast majority of military supplies air dropped near Kobane had reached the Kurdish fighters they were intended to help, despite an online video showing IS militants with a bundle.
Pentagon officials said a US airdrop had delivered 28 bundles of military supplies to Syrian Kurdish fighters near Kobane on Sunday and reported that one had fallen into the hands of IS militants.
The Pentagon later said it had targeted the missing bundle in an air strike and destroyed it.
