Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. US Steps Up Explosive Package Probe VOA News 30 October 2010 A handout picture released by the Emirates News Agency (WAM) shows a printer found in a US-bound parcel displayed by police in the Gulf emirate of Dubai, 30 October 2010 Photo: AFP A handout picture released by the Emirates News Agency (WAM) shows a printer found in a US-bound parcel displayed by police in the Gulf emirate of Dubai, 30 October 2010 The United States, Yemen and Britain are searching for suspected terrorists who tried to send two packages containing explosives from Yemen to Jewish places of worship in the U.S. city Chicago. U.S. President Barack Obama on Friday called the intercepted packages a "credible terrorist threat."  The president said the packages originated in Yemen, but he stopped short of implicating the al-Qaida branch in Yemen, which has long said it wants to attack the United States.  Officials say preliminary tests suggest at least one of the packages contained the explosive used in a failed al-Qaida-linked plot to bomb a U.S. plane last year. Yemeni President Ali Abdullah Saleh has pledged full cooperation with the investigation into the packages. The packages were found in planes in Britain and Dubai Friday, prompting intensified security and searches of cargo planes at airports in the eastern United States. U.S. officials say the packages were discovered after Saudi Arabian intelligence passed the U.S. information related to the plot. Some information for this report was provided by AP, AFP and Reuters. .