London open: Ukraine concerns dampen stocks early on

- L&G, G4S, Sainsbury and ITV lead risers- WM Morrison, ex-div stock provide a drag- Ukraine tensions continue to rise- Markets nervous ahead of Yellen speechtechMARK 2,784.08 -0.29%FTSE 100 6,774.00 -0.36%FTSE 250 15,870.07 -0.43%Ongoing tensions in Ukraine and a host of mixed corporate earnings sent UK markets lower on Wednesday.The FTSE 100, which hit a two-month high of 6,822.42 on Friday, was in negative territory for a second straight day, trading down 0.3% at 6,779 early on.As fighting continues across cities in eastern Ukraine, pro-Russian separatists in the region of Donbass said they will hold a referendum on secession on Sunday May 11th. The US Secretary of State has warned that any such attempt would be bogus and further sanctions would be applied on Russia if it went ahead.A top ranking official at the OSCE has called for a cease-fire in Ukraine so that "fair and inclusive" elections can be held on May 25th.Jonathan Sudaria, a dealer from Capital Spreads, said that investors were "tak[ing] more money off the table [...] as the state of affairs in Ukraine begins to deteriorate more rapidly"."It has been a terrible week for violence and discussions in Eastern Europe. The country looks increasingly like it is heading for civil war - thus the change in outlook among investors is understandable," he said.Meanwhile, markets were also showing caution ahead of a speech by Federal Reserve Chair Janet Yellen later this afternoon as she testifies before the Joint Economic Committee of the US Congress. For now at least markets have generally come to believe that the US central bank is in no hurry to initiate rate hikes. However, given the debate about how inflation will act as the labour market continues to recover, her words are likely to be watched very closely. L&G, G4S, Sainsbury and ITV lead risersA bullish Legal & General posted record first-quarter results, with cash flowing strongly and assets under management (AuM) at an all-time high. Thanks to net flows of £3.8bn in the quarter, AuM at Legal & General Investment Management rose 5% year-on-year to £463bn, pushing shares higher early on.Security group G4S was higher after saying trading for the year-to-date has been in line with its expectations, with 4.8% revenue growth in the first three months of the year. Supermarket chain J Sainsbury delivered annual results ahead of expectations this morning, with underlying pre-tax profit rising 5.3% to £798m, compared with forecast for £782m.Broadcaster ITV gained after saying it has acquired an 80% controlling interest in Leftfield Entertainment Group, making ITV Studios US Group the largest unscripted independent producer in the US. Also in demand was industrial engineering firm Meggitt after being awarded a contract by JGC Corporation for the supply of printed circuit heat exchangers for an LNG plant offshore Malaysia.Imperial Tobacco, the company behind brands such as Golden Virgina and Lambert & Butlers, edged higher as it lifted its interim dividend by a tenth despite first-half results being hit by inventory reductions.Vodafone pleased the market after renewing its strategic global alliance partnership with French telecoms peer SFR for a further four years.Ex-div Morrisons tops fallers listA number of stocks were trading lower after going ex-dividend today, including WM Morrison, BP, Unilever, Rexam, Bunzl, CSR, JD Sports, Henderson and Rightmove.Experian disappointed with its outlook statement as it said it faces "a number of one-off headwinds" that will constrain growth in the first half. This comes after the credit checking company recorded organic revenue growth of 5% in the year ended March 31st.Construction materials group CRH also underwhelmed after saying that the improving trends in its European markets during the second half of last year continued in 2014.Engine maker Rolls-Royce fell as it sold its energy gas turbine and compressor business to German engineering group Siemens for £785m.FTSE 100 - RisersLegal & General Group (LGEN) 219.30p +2.72%Sainsbury (J) (SBRY) 339.50p +1.83%ITV (ITV) 188.80p +1.56%easyJet (EZJ) 1,692.00p +1.50%Meggitt (MGGT) 486.70p +1.19%InterContinental Hotels Group (IHG) 2,211.00p +1.19%G4S (GFS) 243.00p +1.12%Compass Group (CPG) 957.00p +0.79%Centrica (CNA) 326.60p +0.74%Royal Bank of Scotland Group (RBS) 327.60p +0.74%FTSE 100 - FallersExperian (EXPN) 1,077.00p -5.03%Morrison (Wm) Supermarkets (MRW) 194.90p -3.51%CRH (CRH) 1,693.00p -2.70%Rexam (REX) 486.40p -2.31%Barclays (BARC) 240.40p -1.88%Antofagasta (ANTO) 771.00p -1.60%Persimmon (PSN) 1,356.00p -1.60%BHP Billiton (BLT) 1,885.00p -1.41%HSBC Holdings (HSBA) 596.30p -1.29%Bunzl (BNZL) 1,644.00p -1.26%FTSE 250 - RisersPerform Group (PER) 234.30p +4.41%Xaar (XAR) 777.00p +3.12%Hikma Pharmaceuticals (HIK) 1,621.00p +2.14%NMC Health (NMC) 456.00p +1.33%Savills (SVS) 618.50p +1.14%Afren (AFR) 160.40p +0.88%Marston's (MARS) 148.80p +0.88%Keller Group (KLR) 998.00p +0.86%Grafton Group Units (GFTU) 600.00p +0.84%Elementis (ELM) 283.20p +0.82%FTSE 250 - FallersHenderson Group (HGG) 236.30p -4.02%Partnership Assurance Group (PA.) 129.70p -3.35%CSR (CSR) 546.50p -2.93%Fidessa Group (FDSA) 2,279.00p -2.81%Barr (A.G.) (BAG) 612.50p -2.78%Imagination Technologies Group (IMG) 195.10p -2.11%Grainger (GRI) 219.90p -2.05%Intu Properties (INTU) 290.30p -1.89%Countrywide (CWD) 584.00p -1.85%Polymetal International (POLY) 548.00p -1.79%BC