Those sanctioned include Alexander Abramov and Alexander Frolov, who Britain described as known associates of oligarch Roman Abramovich, himself sanctioned earlier this year, Reuters reported.
Abramov has an estimated net worth of 4.1 billion pounds ($4.7 billion) and Frolov 1.7 billion pounds, the foreign office statement said. They were targeted for their involvement in the extractive, transport, and construction sectors, it added.
Frolov is the former chief executive officer of Evraz, which was also sanctioned by Britain for operating in sectors of "strategic significance to the government of Russia".
"Today we are sanctioning an additional four oligarchs who rely on Putin for their positions of authority and in turn fund his military machine," Foreign Secretary James Cleverly said.
"By targeting these individuals, we are ramping up the economic pressure on Putin and will continue to do so until Ukraine prevails."
The sanctions implemented include travel bans, asset freezes, and transport sanctions, the foreign office said.
RHM/PR