EL PASO, Texas (AP) — More than 4,000 archaeological artifacts looted from Mexico and seized in the U.S. were returned to Mexican authorities on Thursday in what experts say is one of the largest repatriation ever made between the neighboring countries.

The items mostly date from before European explorers landed in North America and include items from hunter-gatherers in pre-Columbian northern Mexico, such as stones used to grind corn, statues, figurines and copper hatchets, said Pedro Sanchez, president of the National Archaeological Council of Mexico.