The Russian ruble slumped 41 kopecks to the dollar to 30.57 and 10 kopecks to the euro to 42.28 in early MICEX trade on Tuesday on increased worries about the ability of European authorities to tackle the euro debt crisis. The value of the bi-currency basket, comprising $0.55 and 0.45 euros, increased 28 kopecks to 35.84 rubles. The doubts about the European Union\'s ability to solve the sovereign debt crisis intensified on Monday, after Bundesbank President Jens Weidmann said that the package of measures adopted at the crisis summit in Brussels last week was not enough to tackle all of the eurozone\'s problems. The Financial Times also reported that Portugal was going to ask the European Union and the International Monetary Fund for changes to its 78 billion euro financial rescue agreement to lift the country\'s debt-stricken economy out of recession. The Russian ruble-denominated RTS stock index fell 1.65 percent to 1,537.50 as of 10:37 Moscow time, while the dollar-denominated MICEX exchange lost 0.37 percent to 1,493.07. In Europe, the FTSE 100 index fell 2.77 percent to 5,544.22, Germany\'s DAX slumped 3.23 percent to 6,141.34 and France\'s CAC 40 lost 3.16 percent to 3,242.84 as of 10:41 Moscow time.