Pietersen said: “This is a huge decision and cricket can now take priority again. All the players I know personally from other countries have expressed their concerns in terms of safety and security."
“What I said to the team was to put it to the back of our minds because the most important thing for us is the one-day series with South Africa, and that means standing up to be counted," the Daily Star quoted Pietersen, as saying.
England had been due to play in the eight-team tournament in Pakistan next month, but the International Cricket Council announced on Sunday that the competition would not take place due to security fears.
South Africa, New Zealand, England and defending champions Australia had expressed doubts over security arrangements.
ICC President David Morgan said: “There was unanimity to postpone the event until October next year. Unfortunately five of the participating nations found it impossible to send their teams to Pakistan because of safety and security concerns."
Pietersen had voiced his opinions but has now turned his attention to going 2-0 up in the five-match series.