Judicial Watch, a conservative group that pushes for government openness, sued in federal court for the National Archives to release thousands of documents from Sen. Hillary Clinton's years as first lady, including calendars and telephone records, the Post said. The group's 2006 Freedom of Information request for the information has gone unanswered, the paper said.

Clinton, D-N.Y., is the front-runner for the Democratic Party's nomination for president.

The Clinton Library has 78 million pages of documents and 20 million e-mail messages from Bill Clinton's administration. Six archivists are working to answer about 300 outstanding Freedom of Information Act requests, CNN reported.

Former U.S. President Bill Clinton hasn't challenged the release of any requested documents, CNN said. But the Clintons in 2002 did ask that direct communications between them be exempt from disclosure, Newsweek reported.