President Vladimir V. Putin on Monday acknowledged for the first time that the bloody assault on a concert hall near Moscow was executed by “radical Islamists,” but he insisted that Ukraine could still have played a role despite the Islamic State’s claim of responsibility.
As Russians grieved, bringing flowers and candles to makeshift memorials across the country, Mr. Putin said that the tragedy was likely ordered by Ukraine, a statement that shifted attention from his government’s security failure and could also help his war effort.
“The question is: Who benefited from it?” Mr. Putin said, referring to the worst attack in the capital in two decades, during a publicly broadcast meeting with government officials. “This atrocity can be just an element in a series of attempts of those who have been at war with our country since 2014,” he said, referring to the Ukrainian government.
Russian investigators have not disclosed any evidence demonstrating that the four suspects, men from Tajikistan who were migrant workers in Russia, have a connection to Ukraine.
In the news reports, Russian state television presented the location of their arrest — the Bryansk region of Russia that borders Ukraine — as evidence of Ukrainian involvement. The reports also suggested that Kyiv could have hired them to mount the attack.
On Monday, Mr. Putin said, “Of course, it is necessary to answer the question, why after committing the crime the terrorists tried to go to Ukraine?” Mr. Putin said. “Who was waiting for them there?”
Mr. Putin listed Ukrainian attacks against the Russian territory, its energy and transport infrastructure, including in Crimea, and said that the armed attack in Moscow could fit into a bigger operation of intimidation by the government in Kyiv.
Ukraine denied any involvement in the attack on the concert hall that killed at least 139 people.
Mr. Putin’s remarks reflected how the Kremlin seemed determined to muster its resources against what it apparently sees as its main enemy: Ukraine, backed by a coalition of Western states. They also added to a long list of issues that Moscow and Western capitals are at odds with.
President Emmanuel Macron of France on Monday seemed to contradict Mr. Putin’s version. He said that his country’s intelligence services and their partners had determined that “an Islamic State entity masterminded the attack and carried it out.” On March 7, the American Embassy in Moscow also issued a rare, specific warning calling on people to avoid large gatherings, including concerts, owing to information that extremists had imminent plans to target such events in the Russian capital.
France on Sunday raised its terror alert to its highest level. Mr. Macron said that the Islamic State entity, which he did not name, had tried to carry out attacks in France in the past few months.
Aleksandr I. Bastrykin, the head of Russia’s top investigative body, said that the number of dead had grown to 139, including three children. Of those, 137 died in the concert hall and two in hospitals, he said. Forty people died because of gunshot wounds, Mr. Bastrykin said.
Tatiana Golikova, Russia’s deputy prime minister in charge of health care, said that 93 people were still hospitalized and that nine were in a very grave condition.
Over the weekend Russian media appeared to be stepping up efforts to pin the blame on Ukraine. On Sunday the evening news shows on Russia’s main television channels featured reports suggesting that Ukraine was responsible.
The main message was that Western countries were pushing a theory that the Islamic State was behind the attack, which took place at Crocus City Hall on the outskirts of Moscow, to shift blame away from Ukraine.
“The United States and Europe understand that any connection between Ukraine and the attack against Crocus City Hall would be suicidal for Kyiv and the whole anti-Russian alliance,” said one anchor, Dmitri Melnikov, in a report on Vesti Nedeli, the flagship weekly news show on Rossiya-1, the main state-owned television network.
The Islamic State has claimed responsibility for the attack. And the United States has said that the assault was the work of an ISIS offshoot, the Islamic State in Khorasan, and that there was no evidence implicating Ukraine.
Three shopping malls belonging to the company that owns the concert hall said that they would be closed indefinitely. Emergency workers continued to clear the debris inside the concert hall.
A general sense of anxiety among Russians was exacerbated by bomb threats on Sunday that prompted the evacuation of shopping malls in Moscow and in other Russian cities.
Tatiana Stanovaya, head of the France-based political analysis firm R. Politik, said that the Russian news outlets’ focus on Ukraine was “purely political in nature and is likely aimed at internal consumption.”
Mr. Macron said that France had offered to cooperate with Russia to investigate the Islamic State affiliate, adding that it would be a mistake to try and divert blame for the attack elsewhere.
“I think that it would be both cynical and counterproductive for Russia itself and the security of its citizens to use this context to try and turn it against Ukraine,” Mr. Macron said.
Dmitri S. Peskov, the Kremlin’s spokesman, said he would not comment on the course of the investigation.
“We urge you to rely on the information that comes from our law enforcement agencies,” Mr. Peskov said in comments reported by the news agency Interfax. He added: “The investigation is ongoing. No coherent theory has been published yet. There was only preliminary data.”
The four suspects, according to their brief appearances in court, were foreign migrant workers who spoke little or no Russian. In videos of their court appearances, they looked severely beaten, and footage of their being tortured during interrogation, which has been verified by The New York Times, circulated widely on social media. One of the suspects, Muhammadsobir Z. Fayzov, 19, was rolled into the courtroom in a wheelchair.
On Monday, a district court in Moscow arraigned three men suspected of acting as accomplices. Mr. Bastrykin, the top investigator, said that they provided an apartment to the suspected terrorists, and a car.
The arrest of the suspects has raised questions about the regulation of labor migration into Russia. Mikhail Sheremet, a lawmaker, told the state agency RIA Novosti that he would push for the reintroduction of capital punishment in Russia.
Aurelien Breeden contributed reporting from Paris.
