The White House has fired a national security adviser who anonymously posted hundreds of comments on Twitter highly critical of U.S. foreign policy and key aides to President Barack Obama.
Jofi Joseph was fired last week after investigators spent months trying to identify the person making the comments under a pseudonym .
Joseph was the nuclear non-proliferation director at the National Security Council and was involved in recent negotiations on Iran's nuclear weapons program. He also worked at the State Department, which has given no details on what his job was.
Joseph told the Politico news website that he takes responsibility for the tweets and apologizes "to everyone I insulted." Joseph said he originally intended his comments as a parody of life in highly politicized Washington, but said they evolved into "a series of inappropriate and mean-spirited comments."
Joseph spared few officials in U.S. national security circles. He criticized Secretary of State John Kerry and his predecessor Hillary Clinton, as well as White House adviser Ben Rhodes.
He questioned the official account of how four U.S. diplomats were killed in Benghazi, Libya last year. Joseph also attacked top Republicans including Sarah Palin, the party's 2008 vice presidential candidate.