Fighting between Kurdish-dominated SDF and Arab allies break out after arrest of latter's leader, opening door to possible reemergence of deadly terror group

Incident comes a day after violence between US-backed Kurdish fighters and Turkish troops left several Kurds dead

Ankara is eyeing military operation in Syrian Kurdish regions, but hopes to get blessing from Moscow first, while Iranians oppose idea

'Turkey is responsible for civilian casualties in the region it controls,' says spokesman for Kurdish-led Syrian Defense Forces

Source said to be Sunni Arab, cultivated by Kurdish intelligence, who turned against Islamic State after terror group killed a relative

Following death of terror leader, Washington makes further moves to protect area's oil fields from extremists, Syria, Russia

Turkey and Kurdish-led SDF also fighting despite truce; clashes underscore risk of spiraling violence as multiple armies jostle for position in volatile border region

Defense Department announcement comes as Trump draws criticism for vowing to protect Syria's fuel reserves even as he heralds withdrawal of American troops

Kremlin tells Kurdish fighters to pull back from frontier or face being 'steamrolled' by Turkish forces

Hours before Ankara set to resume offensive against US allies, leaders of Turkey and Russia agree to create 20-mile deep area free of Kurdish fighters