(CNN) Colorado and Nevada on Monday became the latest states to join California, Oregon and Washington in the Western States Pact, a working group of Western state governors that will coordinate how to reopen from the stay-at-home orders each has issued to limit the spread of the novel coronavirus.

"There's no silver bullet that will solve this pandemic until there is a cure, so we must have a multifaceted and bold approach in order to slow the spread of the virus, to keep our people safe and help our economy rebound," Colorado Gov. Jared Polis, a Democrat, said in a statement on Monday.

Nevada Democratic Gov. Steve Sisolak echoed that message, saying he "believe(s) the sharing of critical information and best practices on how to mitigate the spread, protect the health and safety of our residents and reopen responsibly will be invaluable as we chart our paths forward."

The inclusion of Colorado and Nevada in the Western States Pact bolsters the collaborative approach to reopening embraced by Democratic governors across the country.

California Gov. Gavin Newsom, Oregon Gov. Kate Brown and Washington Gov. Jay Inslee -- all Democrats as well -- stressed earlier this month that their pact would operate in "in a safe, strategic, responsible way."

Newsom thanked Colorado and Nevada in a statement Monday for joining their approach.

"COVID-19 doesn't follow state or national boundaries, and it will take every level of government, working together to get the upper hand on this virus," he said.

Still, the regional alignments come as some states start phased reopenings of their economies even as public health experts have repeatedly stressed the dangers of relaxing social distancing measures too early.

President Donald Trump unveiled new guidelines for governors this month meant to help states loosen their social distancing restrictions and restart their economies.

The milestones suggested by the White House to reopen include a sustained decrease in cases over a 14-day period, a return to pre-crisis conditions in hospitals and capabilities "to quickly set up safe and efficient screening and testing sites" as well as "quickly and independently supply sufficient Personal Protective Equipment" in hospitals, according to the document, which was obtained by CNN.

This story has been updated.