A Kremlin critic who was reportedly shot and killed in Kiev has suddenly turned up alive at a news conference in Ukraine.

Arkady Babchenko, a Russian journalist, was supposedly murdered on Tuesday, but his appearance on Wednesday left family and friends baffled.

The chief of Ukraine's security services told reporters that the agency faked Mr Babchenko’s death in order to catch a man, allegedly hired by Moscow, to kill him.

"I'm sorry, but there was no other way of doing it," Mr Babchenko said during Wednesday's conference.

"Separately, I want to apologise to my wife for the hell that she has been through."

Kiev and national police had reported Mr Babchenko, a strong critic of the Kremlin, was shot multiple times in the back at his apartment building and found bleeding by his wife.

Mr Babchenko, 41, is one of Russia's best-known war reporters, but was forced to leave the country last year because of repeated threats against him and his family.

He had previously been scathingly critical of Moscow's policies, assailing its annexation of Crimea, its support for separatist insurgents in eastern Ukraine and the Russian campaign in Syria.

Vasyl Gritsak, head of Ukraine's security service, initially appeared at the conference before inviting Mr Babchenko to join him.

His appearance sparked gasps and applause from the press.

Mr Babchenko then went on to thank everyone who had been mourning his death.

Wikipedia had listed Mr Babchenko as deceased. Credit: Wikipedia

Mr Gritsak said investigators had identified a Ukrainian citizen who was recruited and paid $40,000 by Russian security services to organise the journalist's killing.

The unidentified man then hired an acquaintance who had fought in the separatist war in eastern Ukraine as the gunman.

Mr Babchenko had claimed that while living in Russia his home address was published online, and that threats were made by phone, email and social media.

Even after he moved to Kiev, the journalist supposedly continued to be threatened.

Foreign Secretary Boris Johnson had been among the high-profile figures to pay tribute to Mr Babchenko.

He had tweeted: "Appalled to see another vocal Russian journalist, Arkady Babchenko, murdered."