The war of words between Donald Trump and Univision escalated Friday, with social-media postings fanning the flames.

Trump sent a letter to Univision CEO Randy Falco on Friday banning Univision employees from using his Trump National Doral hotel and golf course complex, which sits adjacent to one of three large campuses that the Spanish-language media giant has in Miami. Trump’s letter to Falco was first reported by Politico.

Trump’s move may have been in response to an internal memo Univision sent to employees on Thursday telling staffers not to patronize any Trump hotel or property while conducting company business. That came on the heels of Univision pulling the plug Wednesday on its deal to carry the Trump Organization’s Miss USA and Miss Universe beauty pageants after Trump made disparaging remarks about Mexican immigrants in connection with border control issues.

Trump has declared himself a candidate for the GOP president nomination. His remarks about Mexico came on June 16 as he announced his White House bid at a news conference at Trump Tower in New York. “When Mexico sends its people, they’re not sending the best. They’re sending people that have lots of problems and they’re bringing those problems,” Trump said. “They’re bringing drugs, they’re bringing crime. They’re rapists and some, I assume, are good people, but I speak to border guards and they’re telling us what we’re getting.”

The Miss USA telecast had been scheduled to air July 12. Trump has vowed to sue Univision for breach of contract. Also on Friday, he posted on Instagram a photo of a handwritten letter from Univision news anchor Jorge Ramos asking for an interview. The letter, sent to Trump on Thursday, included Ramos’ cell phone number, which spurred more anger among observers of the Trump-Univision feud.

Trump has accused Univision of responding to pressure from the Mexican government. He’s vowed to build a wall along the U.S.-Mexican border to tighten security.

Univision confirmed that it has told its employees not to patronize Trump properties. The company had no comment on the disclosure of Ramos’ telephone number.

A spokeswoman for Trump did not immediately respond to a request for comment.