U.S. President Donald Trump faced scathing criticism on Thursday for an advertisement linking Democrats and immigrants to violent crime, as Democrats and some of his fellow Republicans blasting it as the most racially divisive political ad in three decades.

The online ad features courtroom footage of Luis Bracamontes, an illegal immigrant from Mexico convicted in the 2014 killings of two police officers in Sacramento, California. It cuts between those clips and scenes of migrants, likely a reference to a caravan of up to 3,000 Central Americans headed through southern Mexico en route to the U.S. border.

"Who else would Democrats let in?" asks the ad, which Trump tweeted late on Wednesday. The ad ends with the tag: "President Donald J. Trump and Republicans are making America Safe Again!," a play on Trump's "Make America Great Again" slogan.