What is happening in Afrin? They did not provide further details.
On Sunday, the state-run Anadolu Agency said the Turkish-backed fighters had penetrated 5 kilometers (3 miles) into Afrin as part of the offensive.
Solak said PYD/PKK terrorists forced local Arab, Kurdish and Turkmen to migrate.
Turkey "is the only North Atlantic Treaty Organisation country with an active insurgency inside its borders, and Turkey has legitimate security concerns", Mattis said, referring to the Kurdistan Workers' Party (PKK), which has been engaged in a separatist struggle against Ankara since 1984.
"Our jets took off and started bombing".
But the US-backed Syrian Democratic Forces said earlier on Saturday that the accusations of cross-border attacks were "false" and they would have no choice to retaliate if they were attacked. "We won't fight in the city as we have no problem with civilians", he said. Erdogan has branded this BSF a "terror army", and President Bashar Assad of Syria has called BSF members "traitors".
France on Sunday called for an urgent United Nations Security Council meeting to discuss the Turkish military operation against the Syrian Kurdistan (Rojava) city of Afrin.
Have there been any casualties? The YPG has said Turkey's strikes killed six civilians and three of its fighters and wounded 13 civilians.
Ankara had over recent days expressed fury over a USA plan to train a 30,000-strong body of local fighters, including the YPG, as a "border security force". Another commander said hundreds more were stationed in Atmeh, south of Afrin.
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Turkey launched "Operation Olive Branch", an offensive by Ankara's troops and allied Syrian rebels against the Kurdish People's Protection Units (YPG) in the town of Afrin.
President Erdogan has vowed to wipe out a corridor, first Afrin and then the nearby town of Manbij, from where the YPG has failed to withdraw. The U.S. troop commitment to Syria, he said, is now open-ended.
"As long as the U.S. forces and their allies, including the Takfiri terrorist groups, continue to engage in illegitimate and unlawful practices that are against the worldwide rules and the interests of the Syrian people and are opposed to the will of the legitimate Syrian government, the humanitarian crisis in the Arab country will continue".
Earlier a spokesman for the Kurdish forces that control the Afrin area also reported the raids.
Russia's defence ministry said the main trigger for the escalation was provocative steps taken by the United States aimed at isolating areas with predominantly Kurdish populations.
Are the 2,000 USA troops in Syria really up to that task, should the Turks decide to cleanse the Syrian border of Kurds, or should the Syrian regime decide to take back territory occupied by the Kurds?
Authorities in the Afrin region say more than a million people live there, many displaced from other parts of Syria.
The move comes as Syria once again finds itself on the precipice of a new conflict, after months of reduced violence and a surge in post-war stabilisation plans.
Turkey risks entering a diplomatic minefield with the offensive and the foreign ministry lost no time in inviting the ambassadors of all major powers to be briefed on the offensive.
It began operating in northern Syria in 2016, its participation in an global effort to defeat Islamic State dovetailing with its campaign to block the convergence of Kurdish-run regions.