Donald Trump portrayed migrants as dangerous criminals during a rally in Aurora, Colorado, on Friday, calling for the death penalty for migrants who kill U.S. citizens as he escalates the anti-immigration rhetoric that has fueled his presidential run.

Flanked by posters of alleged members of the Venezuelan gang Tren de Aragua, Trump also said that if elected he would launch a national "Operation Aurora" to target the gang members.

Trump, the Republican presidential candidate, has noticeably hardened his anti-immigration rhetoric in the final weeks of the Nov. 5 election campaign, where he aims to defeat Democratic candidate Kamala Harris. Illegal immigration is a top voter concern, and Trump is seen by most voters as the person best able to address it, opinion polls show.