The Kremlin said Monday that it wants Fox News to apologize for the "insulting" comment its host made about Russian President Vladimir Putin, calling him a "killer."
In an interview broadcast Sunday, President Trump told the network's Bill O'Reilly that he respected Putin.
"He's a killer though," O'Reilly interjected. "Putin's a killer."
In the 16 years that Putin has been either president or prime minister, several Russian opposition leaders, human rights activists, journalists and whistle-blowers were assassinated or died under suspicious circumstances.
The Kremlin, which has always denied involvement in any of those deaths, lashed out at the network. "We think that such words from a correspondent of the Fox News network are unacceptable, insulting," Kremlin spokesman Dmitri Peskov told journalists in a conference call. "And we would, honestly, prefer to receive apologies."
In the interview, Trump also appeared to defend Putin.
"There are a lot of killers," he said in response to O'Reilly's accusation. "We've got a lot of killers. What, you think our country's so innocent? You think our country's so innocent?"
"I don't know of any government leaders that are killers," the news host said.
"Well, take a look at what we've done too. We've made a lot of mistakes," Trump said. "... A lot of killers around, believe me."
Trump cited the U.S. invasion of Iraq. He could have also been referring to drone strikes that have killed civilians or assassinations sponsored by the CIA.
Still, Andrew Kuchins, a senior fellow at Georgetown University and an expert on Russia, called Trump's remarks "inappropriate."
Though the U.S. Army and intelligence services, as well as those of most other world powers, have conducted targeted killings abroad, he said, the deaths of high-profile members of Russia's domestic political opposition are a different matter.
"There the position of moral equivalence gets a lot less defensible," Kuchins said.
He said Trump's comments could also cost him political support, because the public is unlikely to accept the idea that the U.S. is on par with an authoritarian regime, and Congress has widely regarded Russia as an adversary.
Democrats and some Republicans quickly attacked Trump for his remarks.
"When has a Democratic political activists [sic] been poisoned by the GOP, or vice versa? We are not the same as #Putin," Republican Sen. Marco Rubio said on Twitter.
Russia's best known political killing is that of Alexander Litvinenko, a former Russian intelligence officer who called Putin's Russia a "mafia state" and fled to England. In 2006, he was poisoned with radioactive polonium — "probably" under orders from Putin, a British judge ruled last year.
His symptoms resembled those of Yuri Shchekochikhin, who died in 2003 of what also appeared to be a poisoning. A lawmaker and investigative reporter, he had looked at the suspected role of the FSB, the Russian intelligence agency, in a series of 1999 apartment bombings that Putin blamed on Chechen terrorists.
Other critics have been shot to death. They include Boris Nemtsov, a former deputy prime minister who had lambasted Putin's policies and published several reports detailing corruption allegations against him; Natalya Estemirova, an activist who investigated hundreds of cases of human rights violations committed by Ramzan Kadyrov, a pro-Kremlin leader of Chechnya; and Anna Politkovskaya, an investigative journalist who uncovered war crimes committed by the Russian military in Chechnya.
Boris Berezovsky, a powerful oligarch who claimed to have installed Putin as prime minister in 1999 but later fell out with him and fled the country, was found dead in his London apartment in 2013. The cause was hanging, and a British coroner expressed doubts that it was a suicide.
The O'Reilly interview with Trump was not big news in Russia. Kremlin-controlled media reported on it with the headlines "Trump snubs a reporter" and "The deaths of many people are the fault of the U.S."
Russian politicians, public figures and state media have lauded Trump for months while lambasting his predecessor, President Obama. The embrace of Trump follows decades of antagonism between the two countries, with a brief respite during the 1990s.
Trump for his part has praised Putin's leadership qualities and pledged to restore ties with Moscow.
After a telephone conversation last month, Putin and Trump agreed to join forces to fight Islamic State and help resolve crises in the Middle East and North Korea.
Trump told O'Reilly he welcomed cooperation with Russia. "I say it's better to get along with Russia than not. And if Russia helps us in the fight against ISIS, which is a major fight, and Islamic terrorism all over the world, a major fight — that's a good thing."
By the end of the Obama presidency, the relationship between the two countries had hit its lowest point since the Cold War as Moscow had annexed Crimea, supported separatists in eastern Ukraine and helped save Syrian President Bashar Assad's government from crumbling.
Russia accused the U.S. of ignoring its interests in Eastern Europe by pushing for NATO expansion and installing an antimissile defense shield. It also claims that Washington organized nonviolent "color revolutions" in the former Soviet republics of Georgia and Ukraine and financed political opposition in Russia aimed at seizing power and deposing Putin.
Mirovalev is a special correspondent. Staff writer Nina Agrawal contributed from Los Angeles.
2:30 p.m.: This article has been updated with analysis from Russia expert Andrew Kuchins.