MEXICO CITY (Reuters) - The driver of a tour bus that crashed on Tuesday on a quiet road in Mexico’s Yucatan Peninsula, killing 12 people, may have lost control after one of the front tires exploded, the local police chief said.

The bus was carrying 31 passengers, including citizens of the United States, Brazil, Canada and Sweden, on a trip to Mayan ruins when it crashed and flipped over, authorities said. Most of those aboard were travelers on Royal Caribbean cruise ships.

“It seems a front tire of the bus exploded, making it lose control and leave the asphalt,” Carlos Briceno Villagomez, head of the police in the municipality of Bacalar, told Mexican TV network Televisa on Tuesday night.

The government of Quintana Roo state said it was investigating the cause of the accident, which happened on a flat stretch of road and did not appear to involve another vehicle. The driver was injured and has been arrested. A Mexican tour guide was among those killed.

A local civil protection official said authorities were also investigating whether human error contributed to the accident.

The U.S. State Department confirmed on Wednesday that multiple American citizens had died in the crash. Mexican authorities said eight U.S. citizens died.

“We can confirm the deaths of multiple U.S. citizens in #Mexico bus accident, and several injuries. We express our heartfelt condolences to those affected by this tragedy,” State Department spokeswoman Heather Nauert said in a post on Twitter.

One Canadian died in the crash and three others were injured, a spokesman for Canada’s Global Affairs department said. Two Swedish citizens died and two others were injured, Mexican authorities said.

A child was among the dead. Quintana Roo is one of three states on Mexico’s Yucatan Peninsula, a major tourist destination.