Miliband's recommendation that Russia should amend the fundamental law for making possible the extradition of Russian citizens "goes beyond the common sense and should be viewed as an attempt to interfere in our internal affairs," Just Russia faction leader Alexander Babakov was quoted by the Itar-Tass news agency as saying.

"An exacerbation of relations with Britain is a result of Russia's compliance with its constitution that was adopted democratically," former Federal Security Service chief and United Russia member Nikolai Kovalyov said.

"The statement by the British secretary results from his inexperience," Babakov said. "A man appointed to such an important position must know that Russia is not a former British colony but a great nation and Britain has always tried to treat this partner with respect," he said.

British Foreign Secretary David Miliband said on Monday that Britain would expel four diplomats from the Russian embassy in London due to Russia's refusal to extradite a main suspect in the poisoning case of former KGB agent Alexander Litvinenko.

Andrei Lugovoi, also a former KGB officer, was accused of murdering former Russian agent Litvinenko.

Litvinenko died of radioactive poisoning, from Polonium 210, in London on November 23. Experts investigating his death found radiation traces at a dozen locations and on two British Airways airplanes that flew the Moscow-London route.

Lugovoi, a business partner of Litvinenko, met him at a London hotel on November 1. Litvinenko fell ill on that day and died weeks later in a London hospital.

On July 5, Russia's Prosecutor General's Office formally rejected Britain's request for the extradition of Lugovoi.

Russia has said its refusal was based on a constitutional ban on turning Russian citizens over to foreign countries, as well as a European convention that allows signatories to refuse to extradite their nationals.