MEXICO CITY, May 14 (Xinhua) -- At least 21 people have been killed Wednesday in a major highway accident in Mexico's central-eastern state of Puebla, local authorities said.

The tragedy involved three vehicles, and an unspecified number of other people were being treated for injuries, Puebla Interior Minister Samuel Aguilar said in a post on the social platform X.

The crash occurred on Wednesday morning at kilometer 31 of the Cuacnopalan-Oaxaca highway. Ambulances and other emergency services are working at the scene.

Local media reported that a fatal collision occurred when a truck attempted to overtake another vehicle before crossing into the opposite lane and hitting a bus, then crashing head-on into a transport van. ■