"The problem of the PKK terrorist organisation is a sincerity test for everybody.
"I will tell him that this test carries great importance for the region and in determining the fate of our future relations."
Ankara has accused the US and Iraq of not doing enough to prevent PKK fighters from using bases in northern Iraq to stage attacks across the border in Turkey.
Erdogan said he would also seek an explanation from Washington on how US military hardware given to Iraqi forces had ended up in PKK hands.
About 100,000 Turkish troops have massed in the border region in recent weeks after the government authorised raids into the autonomous Kurdish region of Iraq to attack PKK positions.
Washington strongly opposes a Turkish incursion, and so far the military has held back from crossing the border.
But Ankara has been facing intense public pressure to act since the deaths of 12 soldiers in an ambush on October 21.
Erdogan said Turkey still considered diplomacy its favoured route to resolve the problem, but the threat of military action remained.
"Our talks will make them better understand that Turkey's patience has run out and that we are determined to unhesitatingly take all the steps to finish off terrorism," he said.
On Tuesday, security officials said that Cobra helicopters had attacked PKK positions in the mountains of Sirnak province near the Iraqi border. Plumes of smoke could be seen rising from the mountainside.
Meanwhile, Massoud Barzani, president of the Kurdish regional government in northern Iraq, said he regretted Ankara's refusal to hold direct talks on the situation.
"You do not speak to me, then you ask me to do things against the PKK. How can this be?" he asked in Turkey's Milliyet newspaper.
"I am a friend of Turkey but I am not taking orders from Turkey or anyone else."
Ankara has accused Barzani's administration of tolerating and even supporting the PKK.
Barzani urged the PKK to lay down its arms and called on Turkey to consider a political solution to the Kurds' demands for autonomy.