People mourn at a makeshift memorial in front of the Crocus City Hall, a day after a gun attack in Krasnogorsk, outside Moscow, on Saturday. AFP

Russia said on Saturday it had arrested all four gunmen suspected of carrying out a shooting massacre in a concert hall near Moscow, and President Vladimir Putin pledged to track down and punish those behind the attack.

Daesh group claimed responsibility for Friday's rampage but there were indications that Russia was pursuing a Ukrainian link, despite emphatic denials from Ukrainian officials that Kyiv had anything to do with it.

Russia's state Investigative Committee said 133 people had been killed. State TV editor Margarita Simonyan, without citing a source, had earlier given a toll of 143.

In a televised address, Putin said 11 people had been detained, including the four gunmen. "They tried to hide and moved towards Ukraine, where, according to preliminary data, a window was prepared for them on the Ukrainian side to cross the state border," he said.

Putin cast the enemy as "international terrorism" and said that he was ready to work with any state that wanted to defeat it.

"All the perpetrators, organisers and those who ordered this crime will be justly and inevitably punished. Whoever they are, whoever is guiding them," Putin said.

"We will identify and punish everyone who stands behind the terrorists, who prepared this atrocity, this strike against Russia, against our people." The FSB security service said the gunmen had contacts in Ukraine and were captured near the border. It said they were being transferred to Moscow.

Neither Putin nor the FSB publicly presented any proof of a link with Ukraine, with which Russia has been waging war for the past 25 months.

Ukrainian military intelligence spokesman Andriy Yusov told reporters: "Ukraine was of course not involved in this terror attack. Ukraine is defending its sovereignty from Russian invaders, liberating its own territory and is fighting with the occupiers’ army and military targets, not civilians."

A senior Russian lawmaker, Andrei Kartapolov, said that if Ukraine was involved, then Russia must deliver a "worthy, clear and concrete" reply on the battlefield.

Western nations, including the US condemned the attack and expressed sympathy for the Russian people affected.

The UN chief condemned in the strongest possible terms Friday’s deadly terrorist attack at a concert hall outside Moscow.

The Secretary-General of the Gulf Cooperation Council (GCC), Jassem Al Budaiwi, expressed on Friday his strong condemnation and denunciation of the shooting incident in the Russian capital, Moscow.

Agencies