The British government on Thursday blacklisted seven Russian businessmen, imposing travel bans and asset freezes on them because of their "association with the Kremlin," Foreign Secretary Liz Truss said.

Britain imposed sanctions on the owner of the Chelsea soccer club, Roman Abramovich, and Igor Sechin, the chief executive of Russian oil giant Rosneft, slapping them with asset freezes and travel bans because of their links to Russian President Vladimir Putin. 

Oleg Deripaska and "four other Russian oligarchs" are the most high-profile businessmen to be added to the British sanctions list since Russia launched a special military operation in Ukraine and followed criticism that Britain has been acting too slowly.

The action pauses Abramovich's plans to sell the Premier League club, effectively putting the current European champions under government control. However, the government said it was open to selling the club so long as Abramovich himself did not benefit. 

"There can be no safe havens for those who have supported Putin's vicious assault on Ukraine," British Prime Minister Boris Johnson said.

"We will be ruthless in pursuing those who enable the killing of civilians, destruction of hospitals, and illegal occupation of sovereign allies."

British lawmakers called for action to be taken against Abramovich and other Russian oligarchs, with criticism that Johnson's government was acting fast enough compared to the European Union and the United States.

Sechin, who Britain described as Putin's right-hand man, was already under the US and EU sanctions lists, and last week, French authorities seized his yacht.

Since the military operation in Ukraine, Britain has imposed sanctions on about 20 Russian-linked figures. The EU announced fresh sanctions, on Wednesday, against 14 more oligarchs, meaning its restrictions apply to 862 people and 53 entities.

The others added to the British list were Deripaska, who has stakes in En+ Group, Dmitri Lebedev, chairman of Bank Rossiya, Alexei Miller, the chief executive of energy company Gazprom, and Nikolai Tokarev, the president of the Russia state-owned pipeline company Transneft.

In total, Britain said the seven figures, who with the exception of Abramovich had previously been sanctioned by the US or the EU, had a collective net worth of 15 billion pounds. ($19.74 billion).