( CNN) Former Russian spy Sergei Skripal and his daughter, Yulia, are continuing to recover from a nerve agent attack, and their rehabilitation has been “slow and exceedingly painful, ” the daughter said Wednesday.

While Yulia Skripal, 33, spend 20 days in a coma before she was released from the hospital in April and taken to a safe locating, her parent remained hospitalized until last week.

“We are so lucky to have both survived this attempted assassination, ” she said Wednesday from an undisclosed location, her first public appearance since the attack. “I don't want to describe the details, but the clinical treatment was invasive, painful and depressing. Our recovery has been slow and exceedingly painful.”

Yulia Skripal released from hospital