In an online radio broadcast Saturday by the Islamic State, the group said that two "supporters" had carried out the attacks in San Bernardino but stopped short of referring to the couple as members. The FBI said Friday that it is investigating the San Bernardino, California, massacre as an act of terrorism, with officials revealing that the Pakistani woman who teamed with her husband in the slaughter went on Facebook afterward to pledge her allegiance to the leader of the Islamic State. Hundreds of federal agents, in the United States and overseas, are looking for any contacts that the shooters - Chicago-born Syed Rizwan Farook, 29, and his wife, Tashfeen Malik, 27 - might have had with terrorist groups. In his weekly radio address Saturday, President Obama urged the nation to remain united in the wake of Wednesday’s attack. He urged patience as federal law enforcement works to get a “full picture” of the shooters’ motives.