The killing of Russian opposition leader Boris Nemtsov has drawn condemnation from Russian politicians, world leaders, and international rights organizations who were unanimous in their calls for the perpetrators of the crime to swiftly caught and brought to justice.
In Russia, prominent figures from across the country's political spectrum denounced the apparent assassination.
Russian President Vladimir Putin was quick to condemn the killing but also suggested the attack, on a strident Putin critic who was leading national opposition to the Kremlin, was in fact aimed at the government.
According to his spokesman, Dmitry Peskov, Putin said the "cruel murder" had "all the signs of a contract killing" and called it a provocation -- a word meant to suggest Nemtsov was killed in order to blacken the government's reputation.
Nemtsov's slaying adds to a growing list of dead Russian activists, journalists, and politicians who had challenged the Kremlin since the collapse of the Soviet Union.
Former Soviet leader Mikhail Gorbachev said Nemtsov's murder was aimed at "destabilizing the situation in the country, at heightening confrontation" with the West.
Russian opposition lawmaker and leader of the Just Russia party Sergei Mironov called the killing a "clear provocation organized and carried out by those who want to destabilize the situation in Russia."
In reaction to Peskov's statement, chess champion and fellow Putin critic Garry Kasparov linked the assassination of investigative journalist Anna Politkovskaya, the shooting down of Malaysian Airlines Flight 17 over eastern Ukraine -- thought by many to have been blown out of the sky by pro-Russian rebels manning Russian-supplied missiles against Kyiv -- and the Nemtsov shooting.
Dmitry Gudkov of the Just Russia party wrote on Twitter, "This is clearly a political killing. If it wasn't ordered, it was the result of the hatred propagandized by our authorities."
The leader of Russia's Communist Party Gennady Zyuganov said it was "essential to conduct a quick investigation of the incident" and warned someone was attempting to spark a political inferno in Russia.
The head of the Kremlin's human rights council Mikhail Fedotov posted a message on the council's website that said the murder of Nemtsov was a "gunshot at all of Russia."
Exiled former Russian tycoon Mikhail Khodorkovsky said his family was grieving. "We all loved him. With a devil-may-care attitude but a very good guy," Khodorkovsky wrote on Twitter.
U.S. President Barack Obama said in a statement that "the United States condemns the brutal murder of Boris Nemtsov."
The White House statement also called on the Russian government to conduct a "prompt, impartial and transparent investigation" and to "ensure those responsible are brought to justice."
he statement offered sincere condolences to Nemtsov's family, and "to the Russian people, who have lost one of the most dedicated and eloquent defenders of their rights."
U.S. Secretary of State John Kerry said in a separate statement, that Nemtsov "committed his life to a more democratic, prosperous, open Russia."
Kerry said Nemtsov "sought to reform and open Russia, and to empower the Russian people to have a greater say in the life of their country."
Doubts that any Russian investigation would be effective arose quickly, including after images showed police hosing down the murder scene, potentially washing away valuable clues.
Ukrainian President Petro Poroshenko called Nemtsov a personal friend and a "bridge" between the two countries.
Poroshenko wrote on Twitter: "Shock. They killed Boris. It's hard to believe. I have no doubt the killers will be found. Sooner or later. Eternal memory..."
French President Francois Hollande said it was a "hateful murder" of "a courageous and tireless defender of democracy who was committed to the fight against corruption."
German Chancellor Angela Merkel called on President Putin "to ensure that the
murder is investigated and the perpetrators brought to justice".
VygaudasUsackas, the head of the European Union's delegation in Russia said he was shocked by Nemtsov's murder and urged Russian authorities to "swiftly" find those responsible and bring them to justice.
Former U.S. Ambassador to Russia Michael McFaul in tweets called the "murder another dark sign for Russia" and described Nemtsov as "a real patriot":
Thorbjorn Jagland, Secretary-General of the Council of Europe, also reacted to the murder on Twitter: "I am shocked and appalled key opposition leader Boris Nemtsov was shot. Killers must be brought to justice."
Former Georgian President Mikheil Saakashvili expressed "shock" at the news, adding he had known Nemtsov for some 20 years and considered Nemtsov to be a "true patriot of Russia."
Human Rights Watch also urged the Russian authorities to "thoroughly and impartially" investigate the killing.
Based on reporting by Reuters, AFP, AP, TASS, and Interfax