AT&T’s defence of an acquisition of Time Warner could be boosted by a probe into potential interference by US President Donald Trump.

Representative Adam Schiff told news outlet Axios the newly-elected Democratic majority in the US House of Representatives was lining up an investigation into Trump’s actions surrounding the deal. Schiff said it was unclear whether the Department of Justice’s (DoJ) decision to oppose the transaction was the result of genuine antitrust concerns or political pressure.

The investigation could prove timely, as AT&T prepares to do battle once more with the DoJ, which appealed an earlier court decision to approve its $85.4 billion purchase.

While the political probe centres on whether Trump’s opposition was motivated by an ongoing spat with news agency CNN, the investigation could also lay to rest allegations the president influenced the DoJ’s stance toward the deal.

The president spoke out against the deal during his election campaign, expressing concern the acquisition could leave AT&T with “too much concentration of power”, given that a prior acquisition of DirecTV had left the operator as the largest pay-TV provider in the country.

Oral arguments in a DoJ appeal against the decision to approve the acquisition are due to be heard on 6 December.