Tensions between Moscow and London are rising after Russian Deputy Foreign Minister Alexander Grushko said his country will soon find an appropriate response to Britain’s decision to expel four Russian diplomats.

Grushko held a press conference in Moscow on Tuesday during which he hinted that Kremlin is preparing to cease collaboration with Britain in the security sector as a first response to the “provocative” and “immoral” actions took by London.

“This is a direct path to confrontation. Our reaction will be adequate and appropriate,” the diplomat told reporters.

“It is clear that London's policy will complicate if not close the doors for cooperation between law-enforcement bodies on issues directly connected to the security of millions of Russians and Britons.”

These actions come after Russia refused to extradite Andrei Lugovoi, the prime suspect in the murder of former KGB operative Alexander Litvinenko, who died last year in November.

“It is apparent that the (British) sanctions are aimed at politicising the Litvinenko affair. This is no invitation to cooperation,” Gruschko reportedly said.

British investigators previously said there is enough evidence to incriminate Lugovoi, but he can’t face trial for the murder of a British citizen in Russia and urged Moscow to hand him over, despite claims that Russia’s constitution doesn’t permit it.

London decided to expel four high-ranked diplomats in retaliation to the lack of cooperation from Moscow, but didn’t reveal the identities of the four persons.

Russia’s answer quickly emerged, officials saying such an “immoral” measure would rise tensions between the two nations and have “the most serious consequences for Russian-British relations as a whole.”