Police officers guard the cordoned off area around the home of former Russian intelligence officer Sergei Skripal in Salisbury

Salisbury - A former Russian spy who was found slumped on a bench in an English town following a poison attack is no longer in critical condition and "improving rapidly," the hospital treating him said Friday.

Salisbury District Hospital said in a statement Sergei Skripal was "responding well to treatment" and "no longer in a critical condition".

The hospital in southwest England issued the statement after Skripal's daughter Yulia, who is also recovering from the March 4 attack that Britain blames on Moscow, made her first public comments about the incident in a police statement on Thursday.  

"Following intense media coverage yesterday, I would like to take the opportunity to update you on the condition of the two remaining patients," hospital director Christine Blanshard said.

"As Yulia herself says, her strength is growing daily and she can look forward to the day when she is well enough to leave the hospital.

"I also want to update you on the condition of her father, Sergei Skripal. He is responding well to treatment, improving rapidly and is no longer in a critical condition."

The incident triggered a wave of tit-for-tat diplomatic expulsions and inflamed tensions between Russia and Western governments.

London blames Russia but the Kremlin denies any involvement. Britain says the poisoning was carried out with a military-grade nerve agent developed by the Soviet Union.