US media giant Buzzfeed has ended a "significant" advertising deal with the Republican Party, citing opposition to Donald Trump’s policies.

CEO and founder Jonah Peretti told staff the contract was signed before the billionaire had solidified his position as its presumptive presidential nominee.

The ads were due to run over the coming months as part of an agreement worth over €1.1 million, according to Politico.

In an email shared by the website, Mr Peretti wrote: "The tone and substance of [Donald Trump's] campaign are unique in the history of modern US politics.

"Trump advocates banning Muslims from traveling to the United States, he’s threatened to limit the free press, and made offensive statements toward women, immigrants, descendants of immigrants, and foreign nationals.

"Earlier today, Buzzfeed informed the RNC that we would not accept Trump for President ads and that we would be terminating our agreement with them.

"The Trump campaign is directly opposed to the freedoms of our employees in the United States and around the world and in some cases, such as his proposed ban on international travel for Muslims, would make it impossible for our employees to do their jobs."

Mr Peretti added that the decision would "have no influence" on coverage of the US election campaign.  

"We certainly don’t like to turn away revenue that funds all the important work we do across the company," he said.

"However, in some cases we must make business exceptions: we don’t run cigarette ads because they are hazardous to our health, and we won’t accept Trump ads for the exact same reason."