Russian Federation on Wednesday criticized Turkey's airstrikes against Kurdish forces in Syria and Iraq, saying they hindered efforts to combat the Islamic State group, as Turkish troops and Syrian Kurdish fighters traded fire across the increasingly tense frontier.
The Syrian Observatory for Human Rights war monitor reported clashes between Kurdish fighters and Turkish forces along the border near Darbasiya.
"We have expressed those concerns to the government of Turkey directly", Toner added.
Ankara sees the PKK and the Kurdish forces in the Syrian Democratic Forces - known as the YPG - as closely linked, while the United States views them as distinct organizations.
American officials expressed indignation at the Turkish bombing, which killed as many as 20 Kurdish fighters in Syria and, according to the USA military, five Kurdish peshmerga troops in a coordinated attack across the border in northern Iraq.
Ankara has bombed the YPG in northern Syria for months, calling it a "terrorist" group because of its ties to the PKK, which has been waging a deadly insurgency against Turkey since 1984. We told them to pull their troops 20-30km south away from our borders.
Col. John Dorrian, a USA military spokesman, said the lead time failed to provide adequate notice to reposition American forces or warn Kurdish groups with whom the United States is partnering against the Islamic States.
Foreign Minister Mevlut Cavusoglu said on Wednesday that the Turkish military had informed Washington and Moscow on the attack a day earlier that targeted Kurdish-dominated areas in Syria and neighboring Iraq.
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The bombing aimed to erode IS's capabilities in Afghanistan, but it was also seen as a warning to the much bigger Taliban group. The attackers all carried valid passes to the base, security sources told AFP, and were dressed in Afghan army uniforms.
Kurdish outrage erupted after Turkish bombers struck Kurdish fighters in Iraq's Sinjar province and northeast Syria on Tuesday and killed at least 20.
The United States expressed concern over the attack, saying Turkey didn't coordinate with the US -led anti-terror coalition.
Dorrian said the USA had troops in Syria, within six miles of the Turkish air strikes, and "we let the Turks know that the amount of time that was being provided for the strikes was inadequate for us assure safety of our forces on the ground". US officials said that they had asked Turkey not to proceed without proper coordination but that the request was ignored.
Turkey views the group as an extension of the Kurdistan Worker's Party, or PKK, a Turkish insurgent group that has conducted a decades long insurgency that's killed thousands.
Sahin is one of the senior members of the terrorist group.
Turkish President Tayyip Erdogan has said he will not allow Sinjar, around 115 km (70 miles) from the Turkish border, to become a "new Qandil", referring to a PKK stronghold in Iraq near the borders with Turkey and Iran.
Turkey also killed six Kurdish peshmerga fighters in northern Iraq on Tuesday in an apparent accident.