Officials in Moscow have rejected allegations by Ukraine that the Kremlin was behind the killing of a dissident Russian journalist in Kyiv.
Arkady Babchenko was shot in the back on May 29 outside his apartment in Kyiv, where he lived in exile.
The 41-year-old's death stunned colleagues and added to tension between Moscow and Kyiv, whose ties have been badly damaged by Russia's seizure of Crimea and backing for separatist militants in a devastating war in eastern Ukraine.
In a post to Facebook just hours after news of Babchenko's death emerged, Prime Minister Volodymyr Hroysman said, "I am convinced that the Russian totalitarian machine could not forgive his honesty and principled position."
"The Ukrainian prime minister is already talking about how it was done by Russian secret services. An investigation has not yet begun.... This fashion of conducting international affairs is very sad," Russian Foreign Minister Sergei Lavrov was quoted as saying at a Moscow press conference on May 30.
Kremlin spokesman Dmitry Peskov later echoed Lavrov's comment, saying such allegations were part of an anti-Russian smear and demanded Ukraine conduct a "real" probe.
"We strongly condemn this killing and hope for a real, and not a sham, investigation into determining who ordered it," Peskov said, adding that Ukraine had become a "very dangerous place" for journalists.
Aleksandr Bortnikov, the head of Russia's Federal Security Service (FSB), said Ukrainian allegations that the FSB was behind the killing of Babchenko were nonsense and a provocation, the Interfax news agency reported on May 30.
In London, U.K. Foreign Secretary Boris Johnson said he was "appalled by the killing of Babchenko."
"Appalled to see another vocal Russian journalist, Arkady Babchenko, murdered," Johnson said on Twitter. "We must defend freedom of speech and it is vital that those responsible are now held to account."
Kyiv police chief Andriy Krishchenko said in televised comments late on May 29 that police were assuming Babchenko was targeted for his work. "The first and the most obvious version is his professional activities," he said.
But in Moscow, Russia's Investigative Committee distanced the Kremlin from the killing -- saying it had launched its own criminal investigation into Babchenko’s death.
"The Russian Investigative Committee is not going to ignore brutal crimes against Russian citizens," committee spokeswoman Svetlana Petrenko said.
Russia's Foreign Ministry issued a statement to "demand the Ukrainian authorities do everything in their power for an immediate investigation," adding that Moscow hoped "the relevant international agencies and nongovernmental organizations will take the investigation process under their control."
'Pool Of Blood'
Kyiv police spokeswoman Oksana Blyshchyk said police received an emergency call on May 29 from doctors who said a woman called them to say she had "found her husband at home in a pool of blood."
Ukrainian parliamentary deputy Anton Herashchenko, who is also an aide to the interior minister, said Babchenko had just returned home from a nearby grocery store and was opening his apartment door when an assailant waiting in the stairwell shot him multiple times in the back.
"Arkady's heart stopped in the ambulance on the way to the hospital" in Kyiv, Herashchenko said in a Facebook post.
Meanwhile, in an indication that at least one witness saw the assailant, police in Kyiv late on May 29 released a sketch of a main suspect.
Outside Babchenko's apartment building, a small crowd gathered late into the evening, with some of his reporter colleagues expressing shock at his killing, and other people wiping tears from their eyes.
Many of Babchenko's colleagues in Kyiv and elsewhere were quick to pin blame on Russian intelligence agencies, and highlighted the fact that Babchenko had fled Russia for the Ukrainian capital, believing it would safer.
"Fear brought him here," Yury Matsarsky, a former reporter for Kommersant FM radio working in Kyiv, told Current Time, the Russian-language TV network run by RFE/RL in cooperation with VOA.
Dmitry Muratov, the former longtime editor for the independent Russian newspaper Novaya Gazeta, said the killing recalled the murder of one of Russia's best-known commentators, Anna Politkovskaya, who was killed, execution-style, inside her apartment building in Moscow in 2006.
"Arkasha would shoot straight from the hip every day in such a brazen manner that even those close to him felt uneasy sometimes," wrote Pavel Kanygin, a journalist for Novaya Gazeta, referring to Babchenko by his nickname.
"This is a terror attack against the journalism community both in Russia and Ukraine. The killers attacked all of us by choosing the most sincere, noisy, and brave one, the one who is in the public eye," Kanygin said in a Facebook post.
Babchenko was well-known for his criticism of the Kremlin.
His reporting about Moscow's support for pro-Russia separatist fighters in eastern Ukraine brought him severe criticism by Russian state media and from Russian officials.
The media watchdog for the Organization for Security and Cooperation in Europe (OSCE) condemned Babchenko's slaying and called for the killer to be swiftly brought to justice.
"I am outraged by this horrific act," OSCE media-freedom representative Harlem Desir said in a statement. "I call on the authorities to swiftly and thoroughly investigate the circumstances of this assassination and to bring the perpetrators and those who ordered it to justice."
The Committee to Protect Journalists (CPJ) media watchdog also called for a thorough investigation "to find those responsible for this brutal, silencing crime."
"Babchenko was well known for his critical journalism, and authorities must consider his murder as an attack on press freedom," CPJ Europe and Central Asia coordinator Nina Ognianova said in a statement.
Babchenko told RFE/RL in December 2016 that "all of the elements" of Russia's state "propaganda machine" were engaged against him after he posted comments to Facebook about the crash of a Russian military plane in the Black Sea.
All 92 people on board were killed, including members of the Russian Army’s renowned choir, the Aleksandrov Ensemble, who were traveling to give a performance for Russian troops in Syria.
Babchenko said the reaction by state officials and state media to his remarks was intended to send a signal to Russian society that "we must be in one line; we must express sadness; we must appear sad -- and anyone who doesn’t must be destroyed."
'Forced To Flee'
Babchenko told RFE/RL in late 2016 that State Duma Deputy Vitaly Milonov, Federation Council member Frants Klintsevich, and Russian media like Channel One and Life News were "stitching together some fake news" about him.
Babchenko said: "A major effort is being organized. They aren’t investigating why the plane crashed but instead are persecuting me."
In February 2017, writing for Britain’s The Guardian newspaper, Babchenko said: "I can tell you what political harassment feels like in [President Vladimir] Putin's Russia. Like many dissidents I am used to abuse, but a recent campaign against me was so personal, so scary, that I was forced to flee."
WATCH: Arkady Babchenko speaks to RFE/RL about leaving Russia and living abroad (in Russian, no subtitles)
Babchenko served in the Russian Army during the first separatist war in Chechnya in the 1990s before he became a journalist.
He worked as a military correspondent and wrote for several Russian media organizations, including the Moskovsky Komsomolets daily newspaper and Novaya Gazeta, as well as TV Tsentr, and Channel One TV.
He had been scathingly critical of the Kremlin in recent years. He moved to Kyiv in the autumn of 2017, where he worked as a host for the Crimean Tatar TV station, ATR.
Babchenko is the second high-profile Russian journalist to be killed in Kyiv in less than two years.
Authorities in Ukraine are still investigating the killing of journalist Pavel Sheremet in a car-bomb blast in central Kyiv in July 2016.
Sheremet, a Belarusian-born Russian citizen who made Kyiv his permanent home, was well known as a hard-hitting reporter and commentator who had worked at prominent media outlets in Belarus, Russia, and Ukraine during his decades-long career.
Often critical of political leaders, he had received threats and been harassed on several occasions.