Police tape lines a sidewalk in front of the Tree of Life synagogue in Pittsburgh after the Oct. 27, 2018, shooting attack there. Photo: Reuters / Alan Freed.

A 27-year-old alleged white supremacist was arrested by US federal authorities over the weekend and has been charged with plotting to blow up a synagogue in Colorado.

Richard Holzer was brought into custody at a motel on Friday night shortly after he examined inert explosive devices presented to him by undercover agents.

Holzer’s target was said to be Temple Emanuel in Pueblo, Colorado.

According to court documents, Holzer talked about killing Jews in online forums and shared photos of himself with weapons next to white supremacist symbols.

“I want something that tells them they are not welcome in this town,” Holzer was quoted as saying.

The arrest of Holzer took place shortly after the one-year anniversary of the Tree of Life synagogue massacre in Pittsburgh, in which 11 Jewish worshipers were murdered.