FTSE 100 Index, British benchmark stock market gauge, Thursday decreased by 0.58 percent, or 38.79 points, to 6,597.37, as traders continued to anxiously watch developments between Ukraine and Russia.
The North Atlantic Treaty Organization (NATO) said that the significant increase of Russian troops near Ukraine over the last few days was of "great concern". Meanwhile, Russia has denied the allegations, saying that comments from NATO are misleading.
The Bank of England (BoE), the central bank of Britain, Thursday voted to maintain Bank Rate at 0.5 percent. The bank also voted to maintain the stock of purchased assets, or quantitative easing policy scheme, at 375 billion pounds (633.75 billion U.S. dollars).
The European Central Bank (ECB) also decided to keep monetary policy settings unchanged on Thursday.
Coca-Cola HBC AG led the top losers of the blue chips with a share price drop of 5.31 percent, followed by easyJet (3.43 percent), RSA Insurance Group (3.02 percent), GlaxoSmithKline (2.75 percent) and Anglo American (2.64 percent).
While Sage Group's share price increased by 3.08 percent, topped the gainers of the blue chips. Aviva, Royal Mail, Legal & General Group, ARM Holdings PLC increased by 2.61 percent, 2.53 percent, 2.46 percent and 2.23 percent respectively.
The index has gained 0.18 percent so far this year when adjusted in U.S. dollar.