Vehicles carrying Turkish military personnel and heavy machinery arrived at the border with Syria on Tuesday as Turkey prepared to launch an offensive there, following a surprise move by President Donald Trump to pull U.S. troops out of northeast Syria, leaving Kurdish-led forces - long allied with Washington - vulnerable to attack.
The abrupt policy shift has been widely criticized in Washington, including by members of his own party.
And, in a statement, the Syrian Democratic Forces - a mostly Kurdish militia which Turkey has branded a terrorist group - called the move "a stab in the back." Trump, meanwhile, denied he had abandoned the Kurdish forces, the most effective U.S. partners in fighting Islamic State in Syria.
But Trump praised Turkey on Twitter as a good trade partner, in a softening of tone hours after threatening to "destroy and obliterate the Economy of Turkey" if it acted “off limits” in Syria.
Turkish officials told Reuters that Turkey’s military struck the Syrian-Iraqi border to prevent Kurdish forces using the route to reinforce northeast Syria.
It was not clear what damage was done or whether there were casualties.
And details of the strike were hazy.
Signaling a further potential shift in the region’s power balance, the Kurdish-led forces in Syria said they might start talks with Damascus and Russia to fill a security vacuum in the event of a full U.S. withdrawal from the Turkish border area.
Russia, the strongest foreign ally to Syrian President Bashar al-Assad, said it was not told in advance by Washington or Turkey about any plans to pull U.S. troops from the northeast and said it was watching the situation very closely.