Swiss chemicals company Ineos has bought all the UK North Sea gas fields owned by the DEA Group, which is owned by Russian billionaire Mikhail Fridman's investment fund LetterOne, the companies said on Sunday. In April, Britain's Energy Ministry gave Fridman six months to dispose of oil and gas fields LetterOne bought from German utility RWE, or see their licenses revoked as the West tightened sanctions against Moscow, Reuters reported. "Ineos has been very open about its intention to make strategic investments in the North Sea … It will help our UK petrochemical assets to have ongoing access to competitive energy," INEOS Chairman Jim Ratcliffe said in a statement. The Rolle-based company announced plans last year to make a $1-billion investment in British shale gas exploration with an ambition to become the country's biggest shale gas player. The initial offers submitted in July fell far short of LetterOne's target price of up to $1.2 billion, with the highest offers coming in at around $750 million, several sources close to the process have said.