Washington DC - President Donald Trump on Thursday called the Associated Press a "radical left organization" in the fight over the agency's use of the Gulf of Mexico for the renamed body of water.

Trump in his first month in office dubbed the area the "Gulf of America" and has restricted Associated Press (AP) journalists' access to the White House until the news agency obeys his order.

The White House has blocked AP journalists from Air Force One and the Oval Office, arguing that the agency was ignoring a lawful name change.

"We have a fight with one news organization, AP, a radical left organization – treats us all very badly – and they refuse to acknowledge that the Gulf formerly of Mexico is now called the Gulf of America," Trump said in a speech Thursday to the Republican Governor's Association in the capital Washington.

Donald Trump Trump orders firing of all "Biden-era" US attorneys

"We're holding them out of any news conferences now. I'm sure they'll get sued, and maybe they'll win. Doesn't matter. It's just something that we feel strongly about," he added, without clarifying what he meant about the possible legal action.

The 180-year-old media organization has long been a pillar of US journalism and provides news to print, TV, and radio outlets across the country.

In a style note last month, AP noted that "the Gulf of Mexico has carried that name for more than 400 years" and said Trump's executive order "only carries authority within the United States."