From the Chicago Tribune: Senior Homeland Security Department officials warned Wednesday that the threat to the United States is the highest it has been since the attacks of Sept. 11, 2001, citing the emergence of more foreign terrorist groups, a sharp increase in extremists in this country and the "lone wolf" operator whom authorities worry they may not be able to stop.

"The terrorist threat facing our country has evolved significantly," said Homeland Security Secretary Janet Napolitano. "In some ways, the threat facing us is at its most heightened state since those attacks."

Michael E. Leiter, director of the National Counterterrorism Center, said his concerns included someone operating unbeknownst to authorities and with the means and determination of a Faisal Shahzad, who is accused of parking a car bomb in New York's Times Square last May. The bomb failed to detonate, and Shahzad was arrested as he was boarding a flight out of the United States.

The officials appeared before the House Homeland Security Committee in its first hearing since Republicans took control last month. Rep. Peter T. King (R-N.Y.), the panel's new chairman, is planning more hearings next month into the radicalization of American Muslims.