Several ancient Mayan ruins in Mexico have become inaccessible due to escalating cartel violence, dealing a significant blow to tourism in the southern state of the country.

The Mexican government acknowledged that at least two popular Mayan sites, Yaxchilán and Tonina, are no longer reachable by tourists.

Tour guides in the state of Chiapas revealed to the Associated Press that additional ruins, supposedly open according to the government, can only be accessed by passing through checkpoints controlled by criminal gangs.

Over the past year, drug cartel violence in Chiapas has surged, adversely affecting tourism, a crucial source of economic opportunity for locals in the Mexican state near the Guatemala border, the New York Post reported.

The Yaxchilán and Tonina historic sites have been effectively isolated from travelers, with the former being impacted by violence and the latter by a land ownership dispute, as admitted by Mexican officials.

Tour guides, who requested anonymity for their safety, reported that gunmen frequently line the road to Bonampak, a Mayan site renowned for its murals.

Another tourist spot, Lagartero, is said to be afflicted by cartel members establishing checkpoints where they demand travelers surrender their identification and unlocked cellphones.

Competing cartels in the area have set up checkpoints to monitor each other and their activities.

While the Mexican government asserts that the archaeological sites are secure and claims no harm has come to tourists, many tour guides are unwilling to take the risk and avoid attracting the attention of the cartels.

Written by B.C. Begley