Legislation to allow Britain to hit banks, energy companies and “oligarchs close to the Kremlin” with economic sanctions will be introduced by the government this week, the foreign secretary, Liz Truss, has said. The scheme is the latest attempt by the UK to dissuade the Russian president, Vladimir Putin, from launching an invasion of Ukraine, and was announced hours after Britain said it was willing to deploy more forces to Estonia and other Nato allies in eastern Europe. “We’re going to be introducing new legislation so that we can hit targets including those who are key to the Kremlin’s continuation and the continuation of the Russian regime,” Truss told the BBC’s Sunday Morning programme. “There will be severe costs on an invasion into Ukraine. And we would target Russian financial institutions, we would target energy companies, we will target oligarchs close to the Kremlin,” she added. Both the foreign secretary and the prime minister, Boris Johnson, are expected to visit Kyiv early this week, despite the pressure faced by Downing Street over the “partygate” scandal. A redacted version of Sue Gray’s report is expected to emerge on Monday. Foreign Office sources said Britain’s existing sanctions regime allowed the UK only to target those linked to the destabilisation of Ukraine; the new legislation will permit a wider targeting of the “strategic interests” of the Russian state. Any legislation will probably have to be sped through parliament as about 100,000 troops are massing in Russia and neighbouring Belarus, creating what Truss described as “a real threat of invasion”. The government has been accused of allowing Kremlin-linked money to flow easily through the City of London, and in some cases Russia-linked individuals donating to the ruling party. Last week, the Center for American Progress, a US thinktank close to the president, Joe Biden, warned that “uprooting Kremlin-linked oligarchs will be a challenge given the close ties between Russian money and the United Kingdom’s ruling Conservative party, the press, and its real estate and financial industry”. The thinktank proposed creating a joint US-UK working group to “prod stronger action from the UK government”. When asked about the thinktank report, Truss told the BBC: “We are doing more. We are introducing new legislation.” Britain, in conjunction with the US, has stepped up its rhetoric about the Russian threat to Ukraine, with London warning of a possible coup plot a week ago. Ukraine’s president, Volodymyr Zelenskiy, has talked down the risk, arguing that Kyiv has faced a constant military threat from Moscow since 2014. Russia denies it will invade, although the Kremlin said it was unhappy with the US response last week to its security demands. Moscow wants Ukraine never to be allowed to join Nato and has demanded a broad range of troop withdrawals from former Warsaw pact countries in eastern Europe. On Sunday, it emerged that Britain had offered to double its troop numbers in eastern Europe, where 900 lead a multinational battlegroup in Estonia and 150 in Poland, while Biden said Washington would deploy “not too many” additional forces – a few thousand at most – “in the near term”. Nato’s secretary general, Jens Stoltenberg, said on Sunday that combat troops would not move to Ukraine in the event of a Russian invasion. “We have no plans to deploy Nato combat troops to Ukraine,” he said, adding later: “There is a difference between being a Nato member and being a strong and highly valued partner as Ukraine.”