WASHINGTON-- Authorites from three continents stopped multiple terrorist attacks aimed at the United States from Yemen on Friday. Two explosive packages aimed at Chicago-area and packed abroad cargo jets were seized. "President Barack Obama called the coordinated attacks a "credible terrorist threat," and U.S. officials said they were increasingly confident that al-Qaida's Yemen branch, the group responsible for the failed Detroit airliner bombing last Christmas, was responsible," The LA Times said. "One of the packages was found aboard a cargo plane in Dubai, the other in England. Preliminary tests indicated the packages contained the powerful industrial explosive PETN, the same chemical used in the Christmas attack, U.S. officials said. The tests had not been confirmed," the Star Tribune said.