The Democrats have hit out at Donald Trump for hiring the publisher of right-wing website Breitbart to be his campaign chief.

Stephen K Bannon, the executive chairman of Breitbart News, was hired by the Republican billionaire this month to serve as the head of his campaign.

But the Democrats have raised questions about the content of Breitbart, a right-wing website that frequently publishes transphobic, homophobic and racist articles.

In an ad, they cited a number of the website’s bigoted headlines published under Mr Bannon’s tenure.

Breitbart, which often denies accusations of bigotry by pointing out that editor Milo Yiannopoulos is gay, claimed in one headline: “Big Gay Hate Machine Closes Christian Pizza Parlor”.

Another, reporting a transphobic billboard attacking Caitlyn Jenner, read: “Trannies Whine About Hilarious Bruce Jenner Billboard”.

Elsewhere, the site insists: “The Solution To Online ‘Harassment’ Is Simple: Women Should Log Off”

The Democrats add: “By hiring Bannon, Trump is doubling down on bigoted rhetoric.”

Breitbart News editor-in-chief Alex Marlow said: “Typical Democrats. They were too lazy to find our inflammatory headlines.”

The Trump campaign has not commented on the ad.

Ultra-homophobic former congresswoman Michele Bachmann also recently signed on to advise Donald Trump.

Related: Nigel Farage wages war on ‘political correctness’ at Donald Trump rally