US telecom giant AT&T said it was a mistake to hire Michael Cohen, a longtime personal lawyer and confidante for President Donald Trump, as a consultant

AT&T's top executive said Friday it was a "big mistake" to hire a Donald Trump's personal lawyer as a consultant after the presidential election, but maintained that the telecom giant's actions were legal and "entirely legitimate."

Randall Stephenson, AT&T's chairman and chief executive, also told employees in a message that the company's policy chief Bob Quinn would be retiring following the disclosures of payments to lawyer Michael Cohen, the focus of a series of investigations.

"There is no other way to say it—AT&T hiring Michael Cohen as a political consultant was a big mistake," Stephenson said.

"To be clear, everything we did was done according to the law and entirely legitimate. But the fact is, our past association with Cohen was a serious misjudgment. In this instance, our Washington DC team's vetting process clearly failed, and I take responsibility for that."

AT&T recently acknowledged paying some $600,000 to Cohen, who is under scrutiny for accepting payment from companies and others seeking access to the White House, and for making a $130,000 payment to porn star Stormy Daniels.

"Our company has been in the headlines for all the wrong reasons these last few days and our reputation has been damaged," Stephenson said.

Stephenson said general counsel David McAtee would be taking over the functions of Quinn following his retirement.

AT&T, which is in the midst of a contentious court battle over its mega-deal for media-entertainment group Time Warner, acknowledged hiring Cohen's firm under a one-year contract at $50,000 per month, from January through December 2017.

The company said it hired the firm among "several consultants to help us understand how the president and his administration might approach a wide range of policy issues important to the , including regulatory reform... tax reform and antitrust enforcement, specifically our Time Warner deal."

"Companies often hire political consultants, especially at the beginning of a new presidential administration, and we have done so in previous administrations," a statement added.

It said Cohen approached AT&T in the transition period between Trump's November 2016 election and his January 2017 swearing-in.

Cohen "said he was going to leave the Trump Organization and do consulting for a select few companies," AT&T explained.

"Our contract with Cohen was expressly limited to providing consulting and advisory services, and it did not permit him to lobby on our behalf without first notifying us (which never occurred)," it added.

"We didn't ask him to set up any meetings for us with anyone in the administration and he didn't offer to do so."

The Justice Department sued in late 2017 to block the AT&T-Time Warner deal, and the case is pending in federal court following a seven-week trial.