bill richardson FILE
CNN  — 

Former Gov. Bill Richardson and his team were in Moscow this week and held meetings with Russian leadership, CNN has learned.

The details around those meetings were not immediately clear. Richardson, the former New Mexico governor and diplomat, and his namesake center privately work on behalf of families of hostages and detainees, and the trip comes as the Biden administration works to free two Americans whom the State Department have classified as wrongfully detained: Brittney Griner and Paul Whelan.

A spokesperson for the Richardson Center told CNN on Tuesday that “at this point we are not able to comment on this.”

CNN reported in mid-July that Richardson had been expected to travel to the Russian capital.

Cherelle Griner, the wife of the detained WNBA star, said Wednesday she is “encouraged to hear” about Richardson’s meetings in Moscow.

“We’ve asked Governor Richardson and the Richardson Center to help us, and have been working with them for a while,” Griner said in a statement to CNN. “We are encouraged to hear that they are having meetings in Moscow.”

Asked about Richardson’s trip, a senior Biden administration official told CNN that anyone “who’s going to Russia is going as a private citizen and they don’t speak for the US government.”

The Kremlin said on Wednesday it had no comment on CNN’s report that Richardson had traveled to Moscow.

When asked to confirm if Richardson was in Moscow to discuss negotiations on a possible prisoner swap between Russia and the US, Kremlin spokesman Dmitry Peskov told journalists on a regular conference call that he had nothing to say on the matter.

“There were no meetings in the Kremlin and I have nothing to tell you on this topic,” Peskov said.

State Department spokesperson Ned Price said they “have been in contact with the Richardson Center.”

“We’re not going to comment on the governor’s travel or the governor’s activity,” he said, adding later that the trip “was not coordinated in advance with the Embassy.”

Price said their “concern is that private citizens attempting to broker a deal do not and cannot speak for the US government.”

“Our concern is that anything other than negotiating further through the established channel is likely to hinder the efforts that we have undertaken to see the release of Paul Whelan and Brittney Griner,” Price said at a press briefing Wednesday.

The Biden administration has repeatedly said that working to secure Griner and Whelan’s release, as well as that of Americans wrongfully detained abroad, is a top priority. In late July, US Secretary of State Antony Blinken announced that the US had put forward a “substantial proposal” to try to secure the release of Griner and Whelan. Sources told CNN that proposal included a swap for convicted arms dealer Viktor Bout.

The State Department spokesperson noted that Presidents Joe Biden and Vladimir Putin “established an appropriate channel that these issues would be worked through.”

“That is the channel that we have been using this time. Through that channel, as the secretary said, standing here a couple months ago now, we made a significant offer to the Russians. We have followed up on that proposal repeatedly. Those discussions are ongoing,” he said.

A senior administration official said the offer was proposed to the Russians “through the same channels we used for Trevor Reed,” another American freed from Russia in April.

Although both Biden administration and Russian officials have made mention of use of an established channel, this is the first acknowledgment that the channels being used for the negotiations are the same that led to the prisoner swap and release of Reed.

Former US Ambassador to Russia John Sullivan, was intensely involved in these negotiations to secure Reed’s release and was also involved in discussions related to Griner and Whelan, citing those efforts as a top priority for him.

He departed his post earlier this month. CNN reported Wednesday that President Joe Biden plans to nominate Lynne Tracy, a career diplomat currently serving in Armenia, as the next US ambassador to Russia, according to three sources familiar with the matter.

There are also messages that have been sent through the intelligence channels as part of the ongoing efforts to get Griner and Whelan home, CNN has reported.

Richardson has long worked to free Americans detained abroad, and he played a role in securing the release of Reed, according to a source familiar with the situation. That source told CNN that members of the Richardson Center had traveled to Moscow in February, in the days immediately before the Russian war in Ukraine began, to meet with Russian leadership. Following that visit, the Richardson Center came away with a clear sense of what the Russians were willing to do and how they were willing to do it, which was presented to the White House. Reed was freed in a prisoner swap in April.

This story has been updated with additional details Tuesday and Wednesday.

CNN’s Anna Chernova, Michael Conte, Zahra Ullah, and Kylie Atwood contributed to this report.