Makan Delrahim talked to reporters in Paris on Friday after speaking at a conference there. Bloomberg says he denied further comment citing the Justice Department's lawsuit to block the deal.
AT&T is seeking information about whether Trump has had any influence in the case, Bloomberg reported earlier in the week.
The telecommunications giant is trying to obtain communications between the White House and the Justice Department, which sued to block the deal in November shortly after Delrahim joined the antitrust division.
AT&T wants Delrahim to testify at the trial next month, Bloomberg reported.
The deal would unite a powerhouse communications network with cable television and movie production assets such as Warner Bros. and CNN, the cable news channel often the target of Trump's barbs against the media.
During the 2016 presidential campaign, Trump said, "AT&T is buying Time Warner and thus CNN, a deal we will not approve in my administration because it's too much concentration of power in the hands of too few."
And then last fall, after the Justice Department filed its lawsuit to block the deal, Trump told reporters, "Personally I've always felt that that was a deal that's not good for the country."