(CNN) -- The list of Russians targeted by Western sanctions is expanding. The EU has added a further 12 names to its original 21-strong lists, while the U.S. focused its sanctions on some of the key people from President Vladimir Putin's inner circle.
Here is a selection of some of the most interesting names from the lists:
Surkov is a close aide and adviser to Putin. He is often described as the "Gray Cardinal" of the Kremlin, one of the masterminds behind the current Russian political system. He served as the deputy chief of staff of Putin's presidential office and as Putin's deputy when Putin held the position of prime minister.
Surkov resigned from that position last year.
Valentina Matviyenko, Speaker of the Federation Council
Effectively number three on Russia's power list, and one of the highest-ranking women in Russian politics. Matviyenko is a firm supporter of Putin and rose to power as the governor of St. Petersburg, Putin's home town.
She is credited with bringing major investors into St. Petersburg and transforming the city into an international hub. Several global companies, including General Motors and Nissan invested in the region while it was under her governorship.
Arkady and Boris Rotenberg
The Rotenberg brothers have close links with Putin, having been his sparring partners in judo training for years. Boris is the president of Dynamo Moscow football club, while Arkady is an executive for Dynamo's ice-hockey club.
The U.S. says the two received about $7 billion in contracts for the Sochi Olympic Games. "They have made billions of dollars in contracts for Gazprom and the Sochi Winter Olympics awarded to them by Putin," the U.S. Treasury Department said in a statement announcing the sanctions.
Gennady Timchenko, founder of energy trading company Gunvor
Magnate Gennady Timchenko's activities in the energy sector have been directly linked to Putin, according to the U.S. Treasury. Gunvor is responsible for much of Russia's oil export transactions.
In a statement Thursday, Gunvor said Timchenko sold all his shares in the company on March 19. It added that Putin "has not and never has had any ownership" interest in Gunvor.
Dmitry Kiselev, news anchor
One of the most influential pro-Kremlin journalists in Russia. Known for his highly controversial views. Advocating Russia's anti-gay laws in 2013, he said: "I believe it is not enough to impose fines on gays for engaging in the propaganda of homosexuality among adolescents. We need to ban them from donating blood and sperm, and if they die in car accidents, we need to bury their hearts in the ground or burn them as they're unsuitable for the aiding of anyone's life."
Sergei Ivanov, Chief of staff of the presidential executive office
Ivanov has been Putin's colleague for decades, since their years of service in the Soviet KGB in St. Petersburg. They continued working together in the Federal Security Office in the 1990s and later in politics. Ivanov served as Putin's first deputy prime minister from 2001 to 2007 and was seen as one of Putin's potential successors in 2008.
Vladimir Yakunin, Russian railway chairman
Yakunin is another St Petersburg figure. The Russian Railway chief was in charge of some of the biggest infrastructure projects of the Sochi Winter Olympics.
Yakunin was also involved in a holiday housing community in the countryside outside St Petersburg. Set up in the 90s, media has speculated that Putin was also involved in the housing cooperative, together with Ivanov and Kovalchuk.
Yuri Kovalchuk, Bank Rossiya's largest shareholder.
The U.S. Treasury Department described Kovalchuk as "the personal banker" to Putin and other senior Russian officials.
Bank Rossiya is Russia's 17th biggest bank, with $10 billion in assets, according to a senior U.S. administration official. It has substantial interests in oil and gas.
Elena Mizulina (also known as Yelena Mizulina), a State Duma Deputy
Mizulina was one of the parliamentarians behind Russia's anti-gay legislation and was also a strong proponent of the anti-Magnitsky law, which banned adoptions of Russian orphans by American families.
CNN's Frederik Pleitgen, Nina Dos Santos, Nick Paton Walsh, Susannah Palk and CNNMoney's Mark Thompson contributed to this report.