The White House says an environmental policy adviser to U.S. President Barack Obama has resigned after a controversy involving his past statements.
Van Jones apologized last week for signing a petition five years ago that questioned whether high-ranking U.S. officials had allowed the September 11, 2001 attacks to occur.
Republican members of Congress have criticized Jones, calling his views extremist and saying he has no place in the administration.
In a statement released early Sunday morning, Jones said his opponents are using lies and distortions to distract from the ongoing health care and clean energy debates in the U.S. He also said he cannot ask his colleagues to spend time defending his past.
Jones also apologized for making derogatory comments about Republicans before joining the Obama administration.
White House spokesman Robert Gibbs said Jones' previous comments were not endorsed by President Obama. During an appearance on ABC-TV's This Week Sunday, Gibbs said that in resigning, Jones had decided the agenda of the president was more important than one individual.
Jones worked as an official for the Council on Environmental Quality, specializing in environmentally friendly "green" jobs.
Some information for this report was provided by AP.