Twenty-two victims of the Russia concert hall attack, in which more than 130 people were killed, remain in serious condition in the hospital, health minister Mikhail Murashko said.
Two of them are children, state news agency Tass said.
Russia is still reeling from Friday’s attack in which gunmen killed 139 people in a concert hall on the outskirts of Moscow.
Russian President Vladimir Putin said that the gunmen are “radical Islamists”, but despite all evidence pointing to the involvement of the so-called Islamic State, Mr Putin repeated his accusation that Ukraine could have played a role.
Kyiv has strongly denied any link to the attack.
Four men accused of carrying out the attack appeared before a Moscow court on Sunday on terrorism charges and showed signs of severe beatings. One appeared to be barely conscious during the hearing.
The men are citizens of Tajikistan, authorities said, and were named by investigators as Dalerdzhon Mirzoyev, 32; Saidakrami Rachabalizoda, 30; Shamsidin Fariduni, 25; and Mukhammadsobir Faizov, 19.
They were charged with committing a terrorist attack resulting in the death of others. The offence carries a maximum sentence of life imprisonment.
Russian officials said they detained a total of 11 people over the attack. Another of those detained appeared in court on Monday.
Alisher Kasimov, a citizen of Kyrgyzstan in Central Asia, was charged with renting an apartment to the men accused of carrying out the attack.
A senior Turkish security official confirmed that two of the Moscow attackers had spent a “short amount of time” in Turkey before travelling together to Russia on March 2nd.
One of the attackers, Fariduni, entered Turkey on February 20th, checked into a hotel in Istanbul’s Fatih district the next day and checked out on February 27th, the official said.
The other, Rachabalizoda, checked into a hotel in the same district on January 5th and checked out on January 21st.
The official said Turkish authorities believe the two suspects “became radicalised in Russia” because they were not in Turkey for long.
There was no warrant for their arrest so they were allowed to travel freely between Russia and Turkey, the official said.
The attack on Friday at the Crocus City Hall music venue on Moscow’s western outskirts was one of the deadliest in Russia in years and left more than 180 people injured.
Two days after the affiliate of the so-called Islamic State in Afghanistan, Isis-K claimed responsibility, Mr Putin acknowledged that the killings were carried out by extremists “whose ideology the Islamic world has been fighting for centuries”.
Mr Putin, who declared over the weekend the four attackers were arrested while trying to escape to Ukraine, said investigators have not determined who ordered the attack, but said it was necessary to find out “why the terrorists after committing their crime tried to flee to Ukraine and who was waiting for them there”.
Isis-K claimed it carried out the attack, and US intelligence said it had information confirming the group was responsible.
French President Emmanuel Macron said France has intelligence pointing to “an IS entity” as responsible for the attack.
