Verizon on Thursday threw a warning flag on its deal with Yahoo when the carrier’s general counsel said a recently revealed breach may have affected the Internet giant’s value.

In comments delivered at a reporter roundtable, Verizon General Counsel Craig Silliman said the carrier has a “reasonable basis” to believe the hack had a “material” impact on Yahoo’s worth, the Washington Post reported.

“We’re looking to Yahoo to demonstrate to us the full impact they believe it’s not,” Silliman said.

The comments raise questions about whether or not Verizon will try to renegotiate the terms or price of the deal, or look to utilize an escape clause to exit the transaction entirely.

According to Silliman, Verizon is still gathering information from Yahoo and has a “significant way to go” before it makes any final decision on the matter.

Earlier this week, Verizon CEO Lowell McAdam said the hack wasn’t ideal but the logic of the Yahoo acquisition still made “a lot of sense.” McAdam said Verizon’s investigation into the breach was a little more than halfway complete, and shot down rumors that Verizon would seek a $1 billion cost discount as “total speculation.”

While Verizon now appears to be setting the stage to force a price concession, Yahoo is holding its ground.

In a statement on Thursday, Yahoo said it remains “confident” in the company’s value and will continue to work toward integration with the carrier.