"I hope that during an Afrin operation, these powers will not make the mistake of appearing to be on the same side as a terror organisation", Erdogan said in an apparent reference to the USA during the rally in the northern Turkish city of Tokat.
A senior Syrian Kurdish official said on Sunday that fighting between the YPG and Turkish forces was already under way.
Afrin is controlled by the YPG, a militia considered by Ankara to be a terror group linked to the outlawed Kurdistan Workers' Party (PKK) waging an insurgency inside Turkey.
Erdogan has repeatedly said that Afrin should be cleared of "terrorists" and in November 2016, he said Turkish troops needed to be deployed there.
Rojhat Roj said the shelling of areas in Afrin district, in Aleppo province, killed one YPG fighter and wounded several civilians on Sunday.
Turkey and its Western allies, including the USA, consider the PKK a terrorist organization.
Turkey's Recep Erdogan threatens attack on Syria
Washington opposes those autonomy plans, even as it has backed the SDF, the main partner for the US -led coalition against Islamic State in Syria.
"We expect (the U.S.) to support Turkey in its legitimate efforts" to combat terror, said Erdogan.
The U.S. -led global coalition against Daesh will establish a 30,000-strong new border security force with the SDF - the U.S. -backed group that is largely controlled and manned by the PKK/PYD terrorist organization in Syria - a U.S. military official said Sunday.
In December, the Associated Press reported that the US was developing an expanded training program for Kurdish and Arab border guards in Syria to prevent the resurgence of IS. "It's absolutely not possible to accept this", Kalin said and repeated that Turkey would defend itself.
A spokesman for Turkish President Recep Tayyip Erdogan denounced the USA -led coalition's plans to train a border security force in northern Syria.
"I hope that during an Afrin operation, these powers will not make the mistake of appearing to be on the same side as a terror organisation", Mr Erdogan said in an apparent reference to the United States during a rally in the northern Turkish city of Tokat.
QB Jacob Eason leaving Georgia after losing job to Fromm
As a true freshman, Eason started the final 12 games of the 2016 season after replacing Greyson Lambert in the opener. Georgia quarterback Jacob Eason announced the expected on Friday: He's leaving the Bulldogs.