The first aid convoys from Kurdish-run northeast Syria were allowed to cross into the northwest part of the country that was leveled by the massive earthquakes centered in Turkey, Syrian Kurdish leaders confirmed to Al-Monitor Monday, saying that US pressure had likely forced Ankara to cave.

The breakthrough followed a weeklong standoff between the Kurdish-led, self-described Autonomous Administration of Northeast and East Syria (AANES) and Turkish-backed Sunni rebel groups.

Salih Muslim, co-chair of the Democratic Unity Party — which shares power in the AANES — told Al-Monitor that 55 trucks carrying relief supplies “collected by the people of Deir ez-Zor and Raqqa” and a further 53 trucks containing aid “donated by the people of Manbij” who are all governed by the AANES had crossed via Manbij into Turkish-occupied areas.

Muslim was unable to confirm how far the convoy was permitted to travel, saying, “To be honest we cannot be sure all the aid will get to the victims because of the culture of impunity and lawlessness of the gangs there.” Muslim was referring to various Sunni rebel factions that have been accused by the United Nations and the United States of engaging in lootings, kidnappings, rape and murder in the broad swathes of Kurdish-run territory they seized together with the Turkish army. “I don’t know for certain, but I think American pressure forced them to let the convoys through.”