[JURIST] One or more suspected pipe bombs exploded early Sunday morning outside the federal courthouse in San Diego, California. No warning was given of the blast but no one was hurt. The front entrance of the Edward J. Schwartz US Courthouse [official website] was damaged. No arrests have been made in connection with the explosion but an investigation is continuing. The court will be closed Monday. AP has more.

Although courthouse bombings are relatively rare in the United States, judges and court administrators have been increasingly focused on security issues [NCSC materials] since a spate of attacks on judges in and out of court in 2005, with incidents in Chicago and Atlanta receiving nationwide attention. A 2006 report on courthouse security by the National Center for State Courts nonetheless concluded that security improvements to that point had been "spotty" [CSM report]. In April 2008 Ohio resident David Tuason was indicted for allegedly threatening to blow up the US Supreme Court building [JURIST report] and attack black men, including Supreme Court Justice Clarence Thomas. Other death threats [JURIST report] have been reported against Justice Ruth Bader Ginsburg and now-retired Justice Sandra Day O'Conner.