Stocks markets began Friday's session in a cautious fashion, with the Footsie registering a moderate decline, ahead of the G20 meeting in Moscow.Delegates plan to discuss traditional issues such as the global economic outlook, implementation of the G20 framework agreement for strong, sustainable and balanced growth, as well as financial regulation reforms. The greatest focus for the market, however, will be the issue of the so-called "currency wars". After the G7 issued a statement promising to allow markets to determine exchange rates, there appears to have been some confusion over the message being misinterpreted as allowing Japan to depreciate the yen in order to support its economy. Sentiment was still a little fragile after disappointing fourth-quarter economic growth figures from the Eurozone and Japan. The Eurozone contracted by 0.6% quarter-on-quarter (consensus estimate: -0.4%) while Japan saw its economic activity decline 0.4% on an annualised basis (consensus estimate: +0.4%).Miners hit by Citi downgrades; Johnson Matthey fallsMining peers Randgold and Fresnillo were heavy fallers early on after Citigroup cut its ratings for both stocks to 'sell' and reduced target prices. FTSE 250 peer Petropavlovsk was also lower after Citi downgraded its recommendation to 'neutral'.Similarly, sweeteners and food products firm Tate & Lyle was hit after Exane BNP Paribas lowered its rating to 'neutral'.Chemicals group Johnson Matthey fell after saying that it is to lose commission income from restructuring a metal supply deal with Anglo American Platinum.Mining giant Anglo American gained despite recording $4.6bn of impairment charges in 2012, while underlying earnings took a hit from falling commodity prices, ongoing cost pressures and a loss-making platinum business. The group did however raise its dividend by 15%.Natural gas firm BG Group was in the red after announcing that Chief Financial Officer Fabio Barbosa is stepping down and becoming Chairman of BG South America.Interdealer broker Tullett Prebon sank after being drawn into the LIBOR scandal. Reports suggest that an individual at the firm was part of conversations about rigging the yen LIBOR rate, according to the Financial Times.On AIM, shares in medical technology group Lombard Medical rocketed after its Aorfix product - a flexible stent graft for the endovascular repair of abdominal aortic aneurysms - was approved for commercial sale in the US. FTSE 100 - RisersAnglo American (AAL) 2,072.00p +2.93%Weir Group (WEIR) 2,205.00p +1.61%ARM Holdings (ARM) 933.50p +0.92%Vodafone Group (VOD) 169.00p +0.87%Kazakhmys (KAZ) 755.00p +0.80%Shire Plc (SHP) 2,041.00p +0.69%Compass Group (CPG) 785.00p +0.64%ITV (ITV) 113.90p +0.44%GlaxoSmithKline (GSK) 1,471.00p +0.41%GKN (GKN) 257.70p +0.39%FTSE 100 - FallersFresnillo (FRES) 1,612.00p -2.60%Randgold Resources Ltd. (RRS) 5,655.00p -2.50%Johnson Matthey (JMAT) 2,249.00p -2.17%Kingfisher (KGF) 270.70p -1.81%CRH (CRH) 1,384.00p -1.77%IMI (IMI) 1,166.00p -1.19%Tate & Lyle (TATE) 792.00p -1.19%Tesco (TSCO) 366.60p -1.07%Pearson (PSON) 1,195.00p -0.99%Amec (AMEC) 1,032.00p -0.96%FTSE 250 - RisersDaejan Holdings (DJAN) 3,499.00p +5.84%Kenmare Resources (KMR) 37.00p +2.78%Invensys (ISYS) 352.50p +1.61%Cable & Wireless Communications (CWC) 42.13p +1.52%Salamander Energy (SMDR) 202.80p +1.40%Telecity Group (TCY) 909.00p +1.39%Fidessa Group (FDSA) 1,843.00p +1.26%Grainger (GRI) 134.70p +1.13%Direct Line Insurance Group (DLG) 218.20p +1.02%Computacenter (CCC) 479.40p +0.93%FTSE 250 - FallersTullett Prebon (TLPR) 281.50p -6.35%London Stock Exchange Group (LSE) 1,257.00p -6.26%New World Resources A Shares (NWR) 289.10p -3.28%Rathbone Brothers (RAT) 1,415.00p -2.41%Heritage Oil (HOIL) 208.60p -2.16%ICAP (IAP) 344.50p -1.82%African Barrick Gold (ABG) 304.00p -1.65%Debenhams (DEB) 95.10p -1.55%Man Group (EMG) 109.40p -1.53%Savills (SVS) 526.50p -1.50%BC