Despite credible claims by Islamist terrorists, the secretary of Russia's National Security Council, Nikolai Patrushev, has blamed Ukraine for the attack near Moscow last Friday.
When asked by journalists on Tuesday whether the Islamic State terrorist militia or Ukraine was behind the attack on the Crocus City Hall concert hall, which left at least 139 dead, Patrushev replied: "Ukraine, of course," according to state news agency TASS.
The 72-year-old, who repeatedly appears as an ardent supporter of the Russian war against Ukraine, did not explain how he arrived at this assessment.
Islamic State has already claimed responsibility for the attack in Moscow on several occasions.
Western security authorities and experts also consider this to be credible and suspect the offshoot Islamic State Khorasan Province (ISKP) to be behind the attack. Despite this, Russian representatives have been claiming for days and without providing any evidence that Ukraine could be involved. Kiev strictly rejects this.
Meanwhile, Russian President Vladimir Putin has been somewhat more circumspect. He said he was counting on the Russian General Prosecutor's Office to do everything possible "to ensure that the criminals receive a just punishment, as prescribed by Russian law."
On Monday, Putin confirmed that the attack on Crocus City Hall on Friday evening was carried out by Islamist terrorists. At the same time, he made it clear, as he had done at the weekend, that he sees a Ukrainian link.
Russia wants to know "who ordered the attack," he said. Putin therefore assumes that Islamists carried out the order for the mass murder, but that the masterminds are located elsewhere. He sees the motive in Ukraine, not in Islamic State.
Earlier Tuesday, a Russian court ordered the detention of an eighth suspect following the deadly attack.
The man is a 31-year-old Russian citizen born in the Central Asian republic of Kyrgyzstan, the Russian news agency Interfax reported on Tuesday, citing Moscow's Basmanny District Court.
He is accused of having provided the attackers with a flat before the offence. Interfax reported that the man had denied in court that he knew about the plans, and believed the people who rented the flat were normal tenants.
Last Friday, gunmen stormed the Crocus City Hall in the city of Krasnogorsk near Moscow, killing at least 139 people. Around 200 others were injured.
Following the attack, the chairman of the Russian parliament, Vyacheslav Volodin, said on Tuesday that he believes that the death penalty can be reintroduced quickly in Russia. "Nobody has abolished the death penalty in our constitution or in criminal law," Volodin said during a session in the State Duma.
The Constitutional Court could decide to apply it, he said, adding that no referendums or other decisions are necessary. Until now, there has been a moratorium on the use of the death penalty in Russia.
Leading politicians, including those from the Kremlin party United Russia, have spoken out in favour of reintroducing the ultimate penalty following the terrorist attack near Moscow on Friday.
Turkish security sources said on Tuesday that two of the suspected Moscow attackers had briefly stayed in Turkey and had travelled together from Istanbul to Moscow on March 2.
Both were able to travel freely because there was no arrest warrant out for them, the sources said.
Turkish police have detained 147 suspected Islamic State extremists in raids across 30 cities and provinces, Interior Minister Ali Yerlikaya said on Tuesday.
Yerlikaya had announced another 40 Islamic State suspects were detained on Sunday. The detentions followed the terrorist attack near Moscow.
Meanwhile, the Russian domestic intelligence service FSB announced that it had foiled another attack in the Samara region. A member of the Russian Volunteer Corps, a paramilitary organization which is fighting on the side of Ukraine, was allegedly behind the plan. This could not initially be independently verified.