After the bombing attempt in Detroit US authorities intensify their screening programs at airports causing long waits

US President Barack Obama has vowed to track down "all who were involved" in helping a Nigerian man who attempted to set off explosives aboard a Northwest Airlines flight bound for Detroit. The president made the comment as debate about the incident turns increasingly political. An assertion by Homeland Security Secretary, Janet Napalitano that "the system worked" has drawn strong criticism. Across the United States, air travelers are experiencing long waits and extensive searches as US authorities intensify their screening programs.