The escalating battle between AT&T and smaller rival T-Mobile US got personal Monday night when AT&T kicked T-Mobile’s outspoken chief executive, John Legere, out of its party at the Consumer Electronics Show, according to

The relationship between the two companies, which tried to merge in 2011, has become increasingly testy as they compete for each other’s customers. AT&T, the second-largest U.S. mobile service provider, said last week that it would pay T-Mobile customers to switch.

According to a report, Legere was escorted out of the Las Vegas event by security guards about 15 minutes after Cnet reporter Roger Cheng posted a picture of himself and Legere and tweeted that the executive had crashed AT&T’s party wearing his trademark pink T-Mobile T-shirt.

Around the same time that Legere was being escorted out, AT&T’s mobility chief, Ralph de la Vega, was announcing that his company had won a deal to provide wireless connections to Audi vehicles, beating out T-Mobile US, the No. 4 U.S. carrier, Cnet reported.

According to Cnet, a tech news and review site, Legere went to the party to see a performance by the rapper Macklemore, whose agent gave the executive and his entourage a pass for the party.

AT&T and T-Mobile did not respond to requests for comment, but Legere retweeted multiple postings about the incident, including Cheng’s tweet that Legere was kicked out.

For most of last year, T-Mobile marketing was aimed directly at AT&T. AT&T is most vulnerable to competition from T-Mobile because the companies have the same network technology, which makes it easy for consumers to switch between their services without buying new phones.

On Friday, AT&T offered T-Mobile customers a $200 credit if they switch to AT&T. Legere responded in a tweet directed at AT&T’s chief executive, Randall Stephenson, asking, “Do you really think you can buy them back?”

Legere has been tweeting heavily to build up anticipation about his company’s next competitive move, which was expected to be announced at a CES news conference Wednesday.