Ten sheriffs from three different states are suing Colorado for legalizing marijuana.

The sheriffs are from Colorado, Kansas and Nebraska. They say in a lawsuit filed Thursday that Colorado's 2012 marijuana legalization vote violates federal law and shouldn't be permitted.

The sheriffs were joined by county attorneys from Kansas and Nebraska. They are asking a U.S. District Court in Denver to nullify the marijuana amendment to Colorado's constitution.

The lawsuit is the latest legal challenge to legal weed. Separately, Nebraska and Oklahoma have appealed to the U.S. Supreme Court to strike down marijuana legalization in Colorado. The Supreme Court hasn't said yet whether it will hear that case.

And a group of Colorado citizens have filed their own federal challenge, saying marijuana reduces property values.