Mr. Trump’s order for the American retreat from its military positions at the other end of Syria — along the Turkish border with northern Syria — set in motion the latest flash point of the eight-year-old Syrian war.
That withdrawal gave the implicit blessing of the White House to Turkish troops to enter northern Syria 10 days ago, where they since claimed the capture of about 1,800 square miles of Syrian territory, diminished American influence in the region and opened the door for Russia to fill the vacuum.
Turkey wants to force out a Kurdish-led militia that had used the chaos of the Syrian conflict to create an autonomous region outside the influence of the Syrian central government. The Kurdish-led militia, known as the Syrian Democratic Forces, had operated under the protection of the United States, since its fighters had partnered with the American military in 2014 to push the Islamic State out of the region.
But Turkey considers the militia a threat to its national security since it is an offshoot of a guerrilla movement that has waged a decades-long insurgency against the Turkish state. The Turkish government wants its Syrian Arab proxies to establish a new autonomous zone in northern Syria in order to dilute Kurdish influence along its southern border.
On Thursday, Mr. Pence announced a deal with Turkey that gave American assent to Turkey’s plan, in exchange for a five-day cease-fire that would allow Kurdish fighters to retreat safely from the region.
But the cease-fire has yet to fully take hold. Sporadic shelling continued on Saturday night and smoke could be seen billowing near a strategic town, observers on the border said.
The commander of the Kurdish-led forces, Mazloum Abdi, said in interviews with international news media on Saturday that Turkish troops had refused to let his fighters retreat. In response, the Turkish ministry said there were “absolutely no impediments to withdrawal.”