Shafaq News/ A prominent Russian nationalist writer, Zakhar Prilepin, was wounded in a car bombing that killed his driver on Saturday and investigators said a detained suspect admitted acting on behalf of Ukraine.
Russian officials immediately blamed the attack on Ukraine and the West.
The state Investigative Committee said the writer's Audi Q7 was blown up in a village in Nizny Novgorod region, about 400 km (250 miles) east of Moscow, which it was treating as an act of terrorism. It said Prilepin had been taken to hospital.
The committee released a photograph showing the white vehicle lying overturned on a track next to a wood, with a deep crater beside it and fragments of metal strewn nearby.
The committee later issued a statement saying investigators were questioning a suspect identified as Alexander Permyakov.
"The suspect was detained and, in the course of questioning, he provided testimony that he acted on the instructions of the Ukrainian special services," said the statement, read by a woman in uniform.
The statement said he acknowledged detonating the bomb remotely and fled but was detained.
State news agency TASS quoted security sources as saying the suspect was a "native of Ukraine" with a past conviction for robbery with violence.
Interfax news agency quoted a source in the emergency services as saying Prilepin's condition was serious and doctors would operate on him.
The novelist is an outspoken champion of Russia's war in Ukraine and has boasted of taking part in military combat there. He was the third prominent pro-war figure to be targeted by a bomb since Moscow's full-scale invasion of its neighbour in February 2022.
Russia has blamed Ukraine for the deaths of journalist Darya Dugina and war blogger Vladlen Tatarsky in the two previous attacks, and Kyiv has denied involvement.
Ukrainian presidential adviser Mykhailo Podolyak posted a cryptic comment on Twitter about Saturday's incident, appearing to suggest it was the result of Russian infighting.
Ukrainian news site UNIAN ran an online poll asking readers who "in the pantheon of Russian scum propagandists" should be targeted next after Dugina, Tatarsky and Prilepin.
Russian Foreign Ministry spokeswoman Maria Zakharova wrote on Telegram: "The fact has come true: Washington and NATO fed another international terrorist cell - the Kyiv regime."
She said it was the "direct responsibility of the U.S. and Britain", but provided no evidence to support the accusation.
Officials at the White House, Pentagon and State Department did not immediately respond to requests for comment. No comment was immediately available from Britain's Foreign Office.
It was the second time this week that Moscow has accused Ukraine of carrying out terrorist attacks on behalf of the West, a narrative it appears to be pushing with increasing urgency but which Kyiv and Washington reject as baseless.
On Wednesday, Russia accused Ukraine of trying to kill President Vladimir Putin with a night-time drone attack on the Kremlin. Ukraine denied that too, and the White House said accusations that Washington had a hand in it were "lies".
TASS quoted Kremlin spokesman Dmitry Peskov as declining to comment on Saturday's car bomb in the absence of information from investigators. The agency said former Russian president Dmitry Medvedev had sent a telegram to Prilepin, calling the incident "a vile attack by Nazi extremists".
Prilepin often speaks out in support of the Ukraine war on social media, with more than 300,000 followers on Telegram and his own website and YouTube channel.
He fought for Russian proxy forces in eastern Ukraine’s Donbas region before last year's invasion and led a military unit there, boasting in a 2019 YouTube interview that his unit "killed people in big numbers".
"These people are dead, they are buried and ... there are many of them," he said. "Not a single unit among the Donetsk battalions had such results. It was outrageous chaos what we did there ... Not a single field commander had such results as I had."