"The U.S. has supplied both the PYD and YPG. That is very clear. Both they [the U.S.] and we know well that weapons are supplied on the grounds of fighting against Daesh," Cavusoglu said.
The YPG is the armed wing of the PYD -- the Syrian offshoot of the PKK, which is designated a terrorist organization by Turkey, the U.S. and the EU.
Cavusoglu’s remarks came during a live TV interview early on Thursday as he spoke about recent negotiations with Russia over the Syria crisis.
The minister was critical of U.S.-led coalition forces which he said had failed to supply air support to Turkey-backed opposition fighters taking part in Operation Euphrates Shield against Daesh.
Pointing out that Turkey is in a serious fight against terrorist groups in northern Syria's Al-Bab, Cavusoglu blamed the lack of air support on "the YPG's pressure on the Americans".
He said Turkey would never allow “terror cantons” in the region both for its border security and for the territorial integrity of Syria.
"It is out of the question that the YPG could be at the table [during discussions over the future of Syria]," the minister added.
About efforts by Turkey and Russia to launch a political process in Syria, Cavusoglu said they were working on two issues.
The first, he said, is to declare a nationwide cease-fire, as in Aleppo; and the second is to ensure political negotiations.
"The best solution is a political one," he said. "However, the priority is to ensure a nationwide cease-fire."
Representatives of the Syrian regime and opposition will meet in the capital of Kazakhstan under Turkey and Russia’s guidance, he confirmed.
As for Iran's role in ensuring peace in Syria, Cavusoglu said it was not clear yet if Iran would be the guarantor of any groups.
The Turkish minister rejected media claims that Turkey would accept Bashar al-Assad’s regime in any transition period.
"We still believe that the regime in Syria, which caused the death of 600,000 people, cannot achieve a political transition," Cavusoglu said.
He said any transitional government should be one "which appeals to all".
Syria has been locked in a devastating civil war since early 2011, when the Assad regime cracked down on pro-democracy protests -- which erupted as part of the Arab Spring uprisings -- with unexpected ferocity.