brussels madrid believe russian-based group use online social media heavily promote catalonia independence referendum last month attempt destabilize spain spanish minister say monday spain defense foreign minister say evidence state private-sector russian group well group venezuela use twitter facebook internet sit massively publicize separatist cause swing public opinion behind run-up oct. referendum catalonia separatist leaders deny russian interference help vote know today much come russian territory spanish defence minister maria dolores de cospedal say russian-based internet support group public private try influence situation create instability europe tell reporters meet eu foreign defense minister brussels ask madrid certain accusations spanish foreign minister alfonso dastis also meet say yes proof dastis say spain detect false account social media half trace back russia another 30 percent venezuela create amplify benefit separatist cause re-publishing message post ramon tremosa eu lawmaker pdecat party catalan separatist leader carles puigdemont repeat monday russian interference play part referendum say russia help catalonia help russian fleet recent years despite eu boycott tremosa tweet refer spanish media report spain allow russian warships refuel port vote referendum opt overwhelmingly independence turnout 43 percent catalans favor remain part spain mainly boycott ballot separatist vote plunge spain euro zone fourth-biggest economy bad constitutional crisis since return democracy 1970s dastis say raise issue kremlin moscow repeatedly deny interference accuse west campaign discredit russia nato believe moscow involve deliberately ambiguous strategy information warfare disinformation try divide west break unity economic sanction impose russia follow 2014 annexation crimea u.s. intelligence agencies conclude january russia interfere u.s. election try help president donald trump defeat rival hillary clinton hack release email spread propaganda via social media nato secretary-general jens stoltenberg attend eu meet brussels decline comment spain accusations alliance top commander say last week russian interference concern nato supreme ally commander gen. curtis scaparotti say russian malign influence try sway elections decisions west describe destabilization campaign although directly address catalonia referendum spain see russian interference catalonia separatist vote