The Southern Ute Indian Tribe, in southwestern Colorado, issued a stay-at-home advisory Monday night because of the coronavirus.

“Through the advisory, the Tribe reaffirms the importance of slowing down the spread of COVID-19,” according to a Twitter post. “The Tribe urges all residents of the Reservation to do their part by staying at home unless it is to engage in an essential activity.”

Tribe leaders, on Twitter, posted guidelines on what defines essential activity as well as sharing additional information on the pandemic. Compliance with the advisory, at this time, is voluntary.

The 1,064-square-mile Southern Ute Reservation is in three counties — La Plata, Archuleta and Montezuma. The tribe’s headquarters is in Ignacio and a seven-member Tribal Council governs the tribe, according to its website. Half of the tribe population is under the age of 30.