Hundreds of Border Patrol officers are mobilizing to bolster the president’s crackdown on immigration in snowy Minneapolis, Homeland Security Secretary Kristi Noem said Sunday, as tensions between federal law enforcement and local counterparts flare after an ICE-involved shooting last week left a mother of three dead.

Thousands gathered in Seattle and across western Washington on Sunday for another day of rallies, after the deadly ICE shooting in Minneapolis.

The frenzied crowd flooded the outside of the Hilton Canopy Hotel — and some parts of the interior — blowing whistles and banging on drums while chanting “f–k ICE” and waving various signs calling for...