WASHINGTON — NBC, Fox News and Facebook have pulled an ad by US President Donald Trump’s campaign that critics had labelled “racist”.

The 30-second ad, which was sponsored by Trump’s 2020 re-election campaign and which debuted online last week, featured courtroom video of an illegal immigrant from Mexico convicted in the 2014 killings of two police officers, juxtaposed with scenes of migrants headed through Mexico.

CNN had refused to run the ad, saying it was “racist”. NBC said yesterday that it was no longer running the ad, which it called “insensitive”. Fox News Channel, which Mr Trump has repeatedly named his favourite broadcaster, also said it would no longer run the ad, précising to have made the decision after a review but not elaborating. Facebook said it would no longer allow paid promotions of the ad, although it would allow users to share the ad on their own pages.

Today’s vote, widely seen as a referendum on Mr Trump’s presidency, has been portrayed by both Republicans and Democrats as critical for the direction of the country. At stake is control of both chambers of Congress, and with it the ability to block or promote Mr Trump’s political agenda, as well as 36 governor’s offices.