At least seven passengers were killed and about 20 others were injured as the charter bus they were traveling with rolled off on the frozen roads in southeastern Utah.

The accident took place on Sunday when the bus, which had about 80 passengers on board, crashed about 10 miles north of Mexican Hat, in the Four Corners region where Utah meets Arizona, Colorado and New Mexico.

Al the states mentioned above sent rescue crews to help those in need according to The Salt Lake Tribune. A helicopter was sent by Colorado, but troopers said it could not take off of due to winter storms that have battered the area.

However, the rescue efforts were slowed down by the winter weather and the area's isolation as well. The cell phone service wasn’t working in the region according to Utah Highway Patrol spokesman Cameron Roden.

The dead and the injured were rushed to the nearest hospital, while those who made it safe and sound were transported by a bus sent to the site for this purpose. The bus transported the safe passengers to Blanding.

The Slat Lake troopers informed that four of the dead were male, two were female and the gender of one is unknown.

"[The passengers] are all being taken anywhere they can get people to," Roden said Sunday.

The cause of the crash is still vague. Police officials investigating the case were en route to the scene late Sunday, but as the winter storm will most likely hit the area through the night as well, their job will be seriously upset.