MTN Group on Monday confirmed that a U.S. court had put on hold the $4.2 billion lawsuit against it by Turkish rival Turkcell, pending a separate U.S. Supreme Court decision.The U.S. Supreme Court had heard oral arguments in a high profile case against Royal Dutch Shell this month, a case which may determine whether foreign corporations can be sued in U.S. courts under an 18th century law.The outcome of that decision is likely to determine whether Turkcell can go ahead with its suit against MTN, which claims the mobile operator used bribes and other underhanded means to obtain its license in Iran, which was originally awarded to Turkcell.