“I thought we were close to having an agreement until they came back with, ‘You have to agree now that you’ll allow a follow-up,’ and I don’t see how we can do it,” Giuliani told Reuters.

Lawyers for Trump have been negotiating over a potential interview with Mueller’s team since last year in the U.S. investigation of Russian meddling in the presidential election, which Moscow denies. Trump has denied any campaign collusion, calling the Mueller probe a “witch hunt.”

In a letter to Trump’s lawyers last week, Mueller expressed a willingness to accept written responses on questions about collusion, but did not rule out a possible interview as a follow-up, a person familiar with the matter told Reuters on Tuesday.

After receiving the written responses, Mueller’s investigators would decide on a next step, which could include an interview with Trump, the person said.

But Giuliani said on Thursday that Mueller’s team had stiffened its position in the latest talks.

“They want a commitment” to a follow-up interview, Giuliani said. “We’ve said no, and let’s see how they deal with it.”