KABUL, April 11 (Xinhua) -- Three gold extraction workers, including a father and his son, were killed after water engulfed an artisanal gold mine in northern Afghanistan's Badakhshan province, a police official said on Friday.

The incident occurred in the Shahri Buzurg district, when a sudden surge of water inundated the mine, according to provincial police spokesman Ehsanullah Kamgar.

The victims were all residents of the neighboring Yaftal district, Kamgar said, adding that it remained unclear how many other miners might still be trapped inside.

Security forces were continuing efforts to locate and evacuate any possible survivors, he added.

Deadly accidents are common in Afghanistan's informal mining sector, where non-standard practices, a lack of modern machinery, illegal extraction by unskilled workers, and disregard for safety precautions frequently claim the lives of impoverished laborers. ■