In a Tuesday speech in Ankara, Erdogan described the Kurdish Peoples' Protection Units (YPG) and the Kurdish Democratic Party (PYD) as terror groups, noting, "We do not and will never allow a so-called state to be established by the PYD, YPG in northern Syria.”
"They want to establish a terror corridor in northern Syria reaching the Mediterranean," he noted.
Erdogan reaffirmed Turkey’s determination to continue to fight against PYD and YPG "wherever we find them.”
The Syrian Kurdish fighters control two "cantons" in Syria's northeast as well as the Afrin region to the west. Turkey says PYD and YPG are the affiliates of Kurdistan Workers' Party (PKK), which is considered by Turkey, the US and EU as a terror group.
In August 2016, Turkey staged a cross-border operation in northern Syria, which Ankara said was aimed at purging the border zone of terrorists.
There has been speculations that Turkey may be planning to launch another operation against the YPG to push it out of the town of Afrin.
Erdogan’s remarks come amid Turkey’s opposition to a referendum on independence of Iraq's autonomous Kurdish region scheduled to be held on September 25.
Turkish Foreign Minister Mevlut Cavusoglu is scheduled to visit Iraq on Wednesday to discuss the issue with Iraqi Prime Minister Haider al-Abadi in Baghdad and then with Iraqi Kurdish leader Massud Barzani in Arbil.
Last week, delegations from Iraq’s ruling coalition, the National Alliance, and Kurdistan Regional Government (KRG) met in Baghdad to discuss the possibility of cancelling or delaying the referendum.
The Kurdish delegation reportedly held talks with Prime Minister Abadi, President Fuad Masum and other Iraqi leaders as well as the ambassadors of the United States, Iran and Turkey in Baghdad.
The visit came after US Secretary of State Rex Tillerson formally asked Massoud Barzani, the KRG president, to postpone the referendum.
According to Abdullah al-Zaidi, a negotiator from the National Alliance, a second round of negotiations could be held next week in the Kurdish capital city of Erbil.
On Sunday, Executive Secretary of the Patriotic Union of Kurdistan (PUK) Politburo Mala Bakhtiar said the Kurds will not agree to delay the vote without fixing another date for it.
He noted that, at the political level, Baghdad should commit to settle the issue of disputed regions such as the oil-rich area of Kirkuk and, on the economic side, the Iraqi government should help the Kurds overcome a financial crisis and settle debts owed by their government.
He said the KRG owes up to $12 billion to public works contractors, civil servants and Kurdish peshmerga fighters who have not received salaries for several months.
Baghdad stopped federal payments to the KRG in 2014 after the Kurds began exporting oil independently from Baghdad, via a pipeline to Turkey.
The Kurds say they need the extra revenue to manage the costs of war against Daesh Takfiri terrorists and a large influx of refugees to their region.
Iraqi Prime Minister Haider al-Abadi issued a statement on Sunday, rejecting Bakhtiar’s suggestion to postpone the planned referendum in return for financial and political concessions from Baghdad.
The statement by the Iraqi prime minister said Bakhtiar's remarks were his personal views and did not reflect the negotiations between the two sides.
"The Reuters correspondent, quoting the head of the political office of the Kurdish Patriotic Union, has published some claims which are false and unrealistic, and have never been raised in talks with the Kurdish delegation in Baghdad," it said.
"Moreover, Mala Bakhtiar was not a member of the delegation and was not present during the talks," added the statement.
The Iraqi government has rejected the planned referendum as "unilateral" and unconstitutional. Turkey, Iran and Syria, which together with Iraq have sizable Kurdish communities, also oppose an independent Kurdistan.
Iraq's militia groups which were key to driving out Daesh from much of the country have threatened to expel the Peshmarga from Kirkuk and three other disputed areas - Sinjar, Makhmour and Khanaqin.