(Reuters) - 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.

Militant Islamist group Islamic State 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.

Moscow regional Governor Andrei Vorobyov said 133 bodies had been recovered from the rubble in 24 hours and doctors were "fighting for the lives of 107 people". 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.

Russia's 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 since Moscow invaded 25 months ago. Ukrainian President Volodymyr Zelenskiy said it was typical of Putin and "other thugs" to seek to divert blame.

Ukrainian military intelligence spokesperson Andriy Yusov told Reuters: "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."

Islamic State has a strong motivation to strike Russia, which intervened against it in Syria's civil war in 2015, and security analysts said the IS claim seemed plausible as it fit the pattern of past attacks.