LONDON - England captain Alastair Cook said Tuesday he was "frustrated" at his inability to reveal the reasons behind Kevin Pietersen's international exile, although he promised all would become clear "soon". Despite being England's all-time leading run scorer across all formats, South Africa-born Pietersen was axed by the England and Wales Cricket Board in February following the team's 5-0 Ashes thrashing in Australia. But precisely why he was sent into international exile, with seemingly no hope of return, remains a mystery and Cook was unable to shed any fresh light on Tuesday. "I can't actually answer that question, totally, at this precise moment in time which is incredibly frustrating for me," Cook told Sky Sports News at county side Essex's media day."Everyone will say I'm sitting on the fence, but there are a number of reasons which will become clearer soon. "You have to respect the decision and the position I am in at this precise moment in time," the left-handed opening batsman added. Initially the ECB would would only cite the need for a new "team ethic and philosophy" as the reason behind the axing of the 33-year-old Pietersen, England's leading run-scorer in the Ashes.But, following fierce criticism from the likes of former captain Michael Vaughan regarding such wording and that management ought to be able to handle 'maverick' players, the board clarified its position with another February statement saying the team had to be rebuilt and that to do that "we must invest in our captain Alastair Cook...with everyone pulling in the same direction and able to trust each other". The ECB added: "It is for those reasons that we have decided to move on without Kevin Pietersen." But that statement still left unanswered the question of what precisely Pietersen had done in Australia to deserve such drastic treatment, with some in the England hierarchy saying confidentiality reasons prevented them from revealing precise details. That simply led to more fresh criticism of the ECB amid suggestions they'd rather having malleable 'nice chaps' on board rather than different types of possibly more awkward characters who were nevertheless match-winners. England's recent struggles, culminating with the humiliation of Monday's 45-run defeat by minnows the Netherlands in the World Twenty20 in Bangladesh, where a team without Pietersen and Cook, who does not play in T20 internationals, were dismissed for just 88, have only led to fresh questions. Cook accepted the 'Pietersen issue' would not go away until England addressed it full on, but insisted he couldn't do so at this moment in time."Everyone is going to keep asking that question until we give the answers, but at the moment we just can't so I'd love to talk about something slightly different," said the 29-year-old. Some of Pietersen's celebrity friends, such as television personality Piers Morgan, have subjected the ECB to a constant barrage of social media criticism since England decided they could do without him. If it's arguable how much good Morgan's support has done Pietersen, it's certainly irked the England hierarchy, including Cook, who were all party to the controversial decision."If anyone thinks the decision was taken lightly and without a lot of consideration and a lot of thought -- a lot of things went into the decision," Cook said. "It was a tough decision. The decisions will be made clearer in due course. You just have to respect that at the moment. It is frustrating. That is the position I'm in," he added.