- GKN, Next and Mondi impress, StanChart upgraded - St James's Place and BP fall- Gains capped by geopolitics, upcoming US data- Petra Diamonds sinks as shareholders sell staketechMARK 2,786.59 +0.38%FTSE 100 6,811.75 +0.35%FTSE 250 15,712.91 +0.62%UK stocks snapped a two-day losing streak on Tuesday, helped by strong gains from GKN, Next, Mondi and Standard Chartered.However, upside was limited as investors continued to focus on geopolitical developments and awaited a wave of US economic data later in the week."It's been another fairly slow start to the day in Europe and this is unlikely to change as we head into the US session, as a lack of economic data leaves traders without any form of catalyst for the next big move in the markets," said Market Analyst Craig Erlam from Alpari UK.The FTSE 100 was heading for its first gain in three days, up nearly 0.4% at 6,812 by midday.Consumer confidence, house-price data, economic growth figures and a host of labour-market indicators will be in focus Stateside over the coming days, culminating with the all-important US non-farm payrolls report on Friday. Meanwhile, Wednesday will see the latest policy decision from the Federal Reserve.Investors will also be keeping an eye on the ongoing Ukraine crisis today with EU leaders expected to approve fresh sanctions on Russia, including measures imposed on banks and energy companies.Continued fighting between Israel and Hamas was also weighing on risk appetite as markets watched the situation closely after blasts in Gaza City and Eshkol yesterday. Over 1,000 Palestinians have now been killed as a result of the violence.GKN, Next, Mondi and StanChart provide a liftGKN rose strongly after saying that a good performance by its automotive business fuelled 6% higher profits at the engineering group in the first half to £296m. However, a strong pound saw sales fall 1%.Analysts celebrated a confident outlook from high street giant Next which lifted its sales and profit guidance for the full year after a strong first half.Packaging and paper group Mondi also said its bottom line is expected to beat forecasts this year, lifting the stock higher.Emerging-markets bank Standard Chartered was in demand after JPMorgan Cazenove upgraded the stock from 'neutral' to 'overweight' after a "material underperformance" in the shares as of late.Leading the fallers on the FTSE 100 was wealth manager St James's Place despite a seemingly strong first half as it hiked its interim dividend by 40% and posted record funds under management. Analysts at Panmure Gordon highlighted that the company missed consensus estimated with its pre-tax IFRS operating profit.Oil major BP was lower even though it registered a 34% jump in second-quarter profits, as it said that further sanctions imposed on Russia "could have a material adverse impact" on its business and corporate relationships.On the FTSE 250, Petra Diamonds shares sunk following an upbeat trading statement yesterday. However, the miner said today that shareholder Awal Bank, now in administration, sold an 8% holding overnight at 190p per share, compared with last night's closing price of 218p.FTSE 100 - RisersGKN (GKN) 365.90p +6.65%Hammerson (HMSO) 613.50p +3.02%Next (NXT) 6,685.00p +2.53%Mondi (MNDI) 1,086.00p +2.45%Standard Chartered (STAN) 1,249.00p +2.17%Intu Properties (INTU) 326.50p +2.13%Travis Perkins (TPK) 1,652.00p +1.98%Kingfisher (KGF) 300.90p +1.72%Aggreko (AGK) 1,786.00p +1.65%Fresnillo (FRES) 954.50p +1.54%FTSE 100 - FallersSt James's Place (STJ) 767.50p -2.85%Aberdeen Asset Management (ADN) 428.10p -1.59%Petrofac Ltd. (PFC) 1,111.00p -1.33%BP (BP.) 491.35p -1.11%easyJet (EZJ) 1,330.00p -1.04%Royal Mail (RMG) 425.70p -1.00%ITV (ITV) 204.00p -0.87%Admiral Group (ADM) 1,469.00p -0.81%British Sky Broadcasting Group (BSY) 897.50p -0.77%BG Group (BG.) 1,204.50p -0.62%FTSE 250 - RisersElementis (ELM) 270.40p +5.05%Rightmove (RMV) 2,294.00p +3.89%Tullett Prebon (TLPR) 248.10p +3.81%Computacenter (CCC) 640.50p +3.31%NMC Health (NMC) 470.00p +3.30%PZ Cussons (PZC) 359.00p +3.19%Barr (A.G.) (BAG) 648.00p +3.10%BTG (BTG) 610.50p +2.69%Debenhams (DEB) 67.90p +2.57%Millennium & Copthorne Hotels (MLC) 586.50p +2.36%FTSE 250 - FallersPetra Diamonds Ltd.(DI) (PDL) 192.40p -11.17%Imagination Technologies Group (IMG) 187.30p -2.70%Renishaw (RSW) 1,840.00p -2.59%Jardine Lloyd Thompson Group (JLT) 1,030.00p -2.46%Exova Group (EXO) 235.00p -2.08%Informa (INF) 484.00p -1.35%Brit (BRIT) 245.00p -1.21%AO World (AO.) 197.80p -1.10%Ocado Group (OCDO) 347.10p -1.05%Euromoney Institutional Investor (ERM) 1,059.00p -1.03%BC