Moscow, Russia - Russia asked Ukraine on Sunday to extradite a number of people, including its security chief, over claims they were behind "terrorist" acts on Russian territory, but Kyiv called the demand "worthless."

In a statement, Russia's foreign ministry repeated a claim that the March 22 attack on a concert hall outside Moscow was linked to Ukraine and accused it of being behind a number of attacks and assassinations on its territory.

Russia has alleged Kyiv was linked to the concert hall attack, despite an affiliate of Islamic State having claimed responsibility.

Invoking two international anti-terrorism conventions, the ministry said it had demanded Ukraine "immediately arrest and extradite" a number of people, including security service chief Vasyl Maliuk.

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It said Maliuk had admitted to having "organized the bombing of the Crimean Bridge in October 2022 and revealed details of the organization of other terrorist attacks."

Crimea was annexed by Russia in 2014 but is internationally recognized as part of Ukraine.

"The Russian side demands that the Kyiv regime immediately cease any support for terrorist activities, extradite those responsible and compensate for the damage caused to the victims," it said.

It was not clear how Russia conveyed its demands, as Ukraine severed diplomatic ties with Moscow shortly after it launched its military assault in February 2022.

Ukraine's SBU security service balked at Russia's statement, which it called "worthless" and "cynical."

"Statements about terrorism are especially cynical coming from a terrorist country," it said.

Earlier this week Maliuk dismissed Moscow's calls to arrest him after giving a television interview detailing extra-judicial killings of Ukraine's opponents in Russia.