Recep Tayyip Erdogan's threats were a warning that a U.S.-Turkish deal to secure Syria's troubled border with Turkey was faltering. He said a Turkish military operation against the U.S-backed Kurdish forces could begin "maybe today, maybe tomorrow."
The Turkish military has been dispatching units and defense equipment to southeastern Sanliurfa province in the past month. Erdogan had expressed frustration, threatening a unilateral operation, but this was his most specific threat amid concerns from the Syrian Kurdish forces of a limited military operation.
"We have given all kinds of warning regarding the (area) east of the Euphrates to the relevant parties. We have acted with enough patience," Erdogan said.
A Turkish military operation, however limited, would put major pressure on the more 1,000 U.S. troops in northeastern Syria and who operate closely with the Kurdish-led forces, whether to implement the security mechanism or in fighting IS.
The Turkish leader has repeatedly expressed frustration with Washington's support for Kurdish groups in Syria. His threats continued despite a deal reached with Washington in August to carry out joint patrols and move Syrian Kurdish fighters away from the border.
The Kurdish-led Syrian Democratic Forces said it is committed to the agreement between Turkey and the U.S. to preserve stability in the region.
"However, we will not hesitate to turn any unprovoked attack by Turkey into an all-out war on the entire border to DEFEND ourselves and our people," SDF spokesman Mustafa Bali tweeted Saturday.
Turkey views the People's Protection Units, or YPG, as an extension of the Kurdistan Workers' Party, or PKK, which has waged an insurgency against Turkey for 35 years.
Ankara and Washington consider the PKK a terror group but they diverge on the issue of the YPG, which forms the core of U.S.-backed Syrian forces against the Islamic State group and is loosely linked with the SDF. Turkey has been infuriated by U.S. support for the group.
Turkey and the U.S. disagree on the size of the area to be monitored by joint patrols, and also on who is to oversee it. Turkey wants its soldiers to monitor an area as deep as 30 kilometers (19 miles). The U.S. and the Kurdish forces have identified an area only as deep as 14 kilometers (9 miles) deep.
Erdogan has said the joint patrols with the U.S. are not enough and appear to be designed to waste time. He called the joint ground and air patrols a "tale."
Three joint U.S.-Turkish ground patrols have run since launching almost a month ago. Kurdish forces have moved away from the frontier and set up new local forces to control border posts, and dismantled fortifications considered a threat by Turkey.
The U.S European Command tweeted Saturday — apparently in response to the Turkish threats — saying the U.S. and Turkish militaries were already working "to address Turkey's legitimate security concerns."
"The Department of Defense will be transparent as each phase of the security mechanism is implemented," it said.
Erdogan said his country wants to send 2 million Syrian refugees now in Turkey to the area it has called a "safe zone." But the Syrian Kurdish group administering the area said only those from the area can return — a number likely to be much smaller.
Erdogan also demanded an answer from the U.S. on whether it will consider the Syrian Kurdish fighters "terrorists."
Associated Press writer Sarah El Deeb in Beirut contributed to this report.