WASHINGTON — A White House national security official was fired after it was discovered that he was behind an anonymous Twitter account that criticized the Obama administration.

Jofi Joseph was nonproliferation director on the National Security Council and was involved in nuclear negotiations with Iran.

His postings on the @NatSecWonk account, which no longer is available on Twitter, often took shots at administration policy and figures, including Secretary of State John Kerry, and members of Congress.

One tweet said: "More people should be asking why John Kerry installed two former aides, both with ZERO foreign policy experience, into top posts at State."

Another tweet said: "That Obama only called Kerry/Hagel AFTER he made decision with his WH aides on going to Hill underscores how all foreign policy is WH-based." The post referred to Obama's surprise decision in late August to seek congressional authorization for military strikes against Syria as punishment for a chemical weapons attack in August.

Joseph could not be reached Wednesday for comment. No one answered the telephone at a number believed to be his.

In a statement to Politico, Joseph said he took "complete responsibility" for the Twitter feed, saying it started as a "parody account." He apologized to those he insulted.

A White House official confirmed that Joseph no longer works for the administration, but declined further comment on personnel matters. It was not immediately clear how officials determined that Joseph was behind the Twitter account.

Joseph began working at the State Department in 2009. Deputy State Department spokeswoman Marie Harf said he was assigned to the National Security Council in 2011 and became an NSC employee last August.

White House spokesman Jay Carney said Wednesday he had no additional information to provide.

Carney said White House staffers cannot access social media sites like Twitter from the White House unless they have an official, authorized account. Carney and many other senior administration officials have official Twitter accounts and they often send several messages a day.