Evan Gershkovich
CNN  — 

President Joe Biden on Thursday said he is “serious” about a prisoner exchange to free wrongfully detained Wall Street Journal reporter Evan Gershkovich from Russia.

“I’m serious about a prisoner exchange. I’m serious about doing what we can to free Americans who are being illegally held in Russia or anywhere else for that matter. And that process is underway,” Biden said at a news conference in Helsinki.

Following comments from the Kremlin, US officials recently confirmed that quiet discussions are underway with Russia to try to secure the release of Gershkovich and fellow wrongfully detained American Paul Whelan.

“We remain in contact with Russian authorities at high levels on these cases to try to figure out a way to bring unjustly detained Americans home, including Evan,” national security adviser Jake Sullivan said last week.

“We have also made clear for months now – even before Evan was detained, as we were dealing with Paul Whelan – that we are prepared to do hard things in order to get our citizens home, including getting Evan home,” he said.

Still, Sullivan sought to temper expectations that progress had been made thus far in the negotiations.

“I do not want to give false hope,” he said. “What the Kremlin said earlier this week is correct: There have been discussions. But those discussions have not produced a clear pathway to a resolution, and so I cannot stand here today and tell you that we have a clear answer to how we are going to get Evan home.”

Gershkovich has been detained in Russia for more than 100 days following his arrest on espionage charges that he, the WSJ, and the US government vehemently deny.

Whelan has been imprisoned for nearly five years, also on espionage charges that he and the US government have denied.

At an event at the National Press Club on Thursday, Danielle Gershkovich spoke about the toll that her brother’s imprisonment has taken on her family.

“I really miss him,” she said, describing him as “a great listener” who “gets the best presents.”

Asked what she plans to do once her brother is released, Danielle said she would first “hug him so hard he won’t be able to breathe,” and her family wants to do a group vacation.

Danielle said she’s “so proud” of the way her brother appears to be handling his ordeal.

“I’m so proud of him,” Danielle said. “I don’t know how he is staying so brave, but it means I have to stay brave for him too.”

US Ambassador to Russia Lynne Tracy has been able to visit Gershkovich twice in the notorious Lefortovo Prison in Moscow, most recently in early July.

“Ambassador Tracy reports that Mr. Gershkovich is in good health and remains strong, despite his circumstances,” a State Department spokesperson said at the time.

CNN’s Allie Malloy contributed to this report.