This blog has now closed. You can read our full report on the attack on Crocus City Hall in Moscow here

State-owned media RIA reports that so many people have turned up to donate blood after the attack that the Buyanov hospital in Moscow has had to ask people to return in the following days.

Maia Sandu, the president of Moldova, has posted to social media to say that they were “terrible images” at the scene of the attack. She said “Moldova condemns all forms of terrorism. Our thoughts are with those who lost loved ones and the injured.”

This blog has closed, read our full report here:

• Full story: shootings and fire at Moscow venue

The roof of Crocus City Hall where gunfire and flames were heard and seen on Friday night is collapsing, RIA reports.

Here are videos emerging through social media:

At least 133 people killed and scores wounded, according to authorities, after gunmen opened fire at Crocus City Hall. Islamic State has claimed responsibility

• Moscow attack – latest updates

Scores of people have reportedly been killed and many wounded in an attack at a concert venue near Moscow.

Here is what we know about the shooting so far:

Vladimir Putin has told the Russian people that Ukraine is linked to the Crocus City Hall terror attack on Friday night that killed at least 133 people. In a video address lasting five-and-a-half minutes, the newly re-elected Russian president said Russian security forces believed they had apprehended all four direct participants in the attack, who were caught heading for Ukraine, which was preparing to receive them over the border. Kyiv has rubbished the claims. Eleven people have been detained in total.

Islamic State has claimed it carried out the attack, which Putin did not mention in his address. He described it as a “bloody, barbaric terrorist act” and said the victims were “dozens of peaceful, innocent people – our compatriots, including children, teenagers, and women”. He said the Russian Federation would “identify and punish everyone who prepared the terrorist attack”.

Ukraine has denied any link to the attack. Presidential adviser Mykhailo Podolyak said attempts to connect the two were “absolutely untenable”. He said: “Ukraine has not the slightest connection to this incident. Ukraine has a full-scale war with Russia and will solve the problem of Russia’s aggression on the battlefield.” Neither Putin nor the FSB publicly presented any proof of a link with Ukraine.

107 people remain in hospital after the attack, including three children, one of whom is described as being in a critical condition. After a drive to receive blood donations in Moscow, the deputy prime minister, Tatyana Golikova, said there was enough “medicine, blood, and dressing materials”. Moscow authorities have said they will pay compensation to those affected, and arrange funerals for those killed.

Putin has declared Sunday a day of national mourning. People have been laying flowers and toys as a tribute to the victims at the site of the attack, and outside Russian embassies all around the world.

Images from inside the venue show that the auditorium has been completely gutted by fire and the roof has collapsed. Russian authorities say people died both from gunshot wounds and the effects of the fire.

The terrorist attack has been widely condemned around the world. David Cameron, Britain’s foreign secretary; Ursula von der Leyen, president of the European Commission, French president Emmanuel Macron, US secretary of state Antony Blinken, and Nato have been among those condemning the attack and offering condolences. Putin spoke to the leaders of Belarus and Uzbekistan by phone. Turkey’s president, Recep Tayyip Erdoğan, also offered his support, saying terrorism was “the common enemy of humanity”.

Reports that Islamic State carried out the attack appear credible to many. Several security analysts said that the claim of responsibility by the Islamic State for the massacre of Russian concertgoers appears to be plausible and fits with a pattern of previous marauding attacks by Islamist militants.

Moscow had been warned. US intelligence gathered information just over two weeks ago that ISPK, a branch of the Islamic State group based in Afghanistan, was eyeing Russia for a terrorist attack. The US embassy in Moscow had said it was “monitoring reports that extremists have imminent plans to target large gatherings in Moscow, to include concerts”. The unusually clear public alert was repeated by the UK.

Zelenskiy speaks out. Ukrainian president Volodymyr Zelenskiy said in his nightly video address on Saturday that Vladimir Putin was seeking ways to divert blame for the massacre at the concert hall near Moscow on Friday. He said it was “absolutely predictable” that Putin had remained silent until the day after the attack before accusing Ukraine of being involved.