By Halit Suleyman and Ayse Aktas

IDLIB, Syria

At least 18 people were killed and dozens injured in fresh Russian airstrikes Wednesday in northwestern Syria, according to a pro-opposition civil defense official.

Omar Ulwan told Anadolu Agency 12 Russian airstrikes targeted a school and a marketplace in Hass town, south of Idlib city.

Hundreds of civilians have reportedly been killed or injured in Russian and Syrian airstrikes since Sept. 19, when the Bashar al-Assad regime announced the end of a week-long truce.

Syria has been locked in a vicious civil war since early 2011, when the Assad cracked down on pro-democracy protests -- which erupted as part of the "Arab Spring" uprisings -- with unexpected ferocity.

Since then, more than a quarter of a million people have been killed and more than 10 million displaced across the war-torn country, according to UN figures.