Six humanitarian aid trucks carrying shelter material and non-food items entered the opposition-held region of northwestern Syria on Thursday, a spokesman for the U.N. Office for the Coordination of Humanitarian Affairs said, three days after a devastating earthquake struck the region.

The convoy, which was originally scheduled to arrive on Monday to assist people affected by the country’s civil war, was the first significant delivery of aid to the territory since the earthquake occurred on Monday morning. The delivery had been stalled by road blockages caused by the earthquake, which has also impeded the work of those employed to verify and transport the aid materials.

The convoy entered Syria from Turkey, using the Bab al-Hawa crossing, which was not functioning after the earthquake and has been the only passage for U.N. aid to opposition-held areas in Syria for the past nine years during the war.

The earthquake has cast a spotlight on the conflict, which broke out in 2011 amid a popular uprising against the government of President Bashar al-Assad. Though violent hostilities have died down considerably in recent years, the conflict continues.

Millions living in Syria’s northwest had been displaced by the war, and were enduring a brutal winter without heating when the earthquake hit. Power outages are creating fuel shortages in hospitals, according to the United Nations, snowfall has impeded rescue efforts there, and temperatures were forecast to dip below freezing on Thursday after rising during the day.

Before the quake, the United Nations sent daily aid convoys into the area, typically including up to 20 trucks.

“This first shipment is a test,” Jens Laerke, the United Nations spokesman, said, to ensure “that the road conditions are such that they can drive.” The organization hopes to get “as much aid into the northwest as possible,” as soon as possible, he said.

Mr. Laerke said the United Nations was also in touch with its partner organizations in Syria to assess what aid is needed in the coming weeks.

Most aid to Syria flows through Damascus, the capital, which is in government-held territory. Because Mr. al-Assad’s government tightly controls what aid goes to opposition-held areas, the cross-border aid deliveries from Turkey have been a lifeline for opposition-held areas in the north for years.