>> reporter: this as speculation continues over trump's nomination for secretary of state. multiple sources familiar with the transition telling cnn exxon mobil chairman and ceo rex tillerson has emerged as the frontrunner. >> he is much more than a business executive. he is world-class player. >> reporter: the possible nomination already sparking sharp criticism from some in the gop establishment, concerned about tillerson's own ties to russia. in 2013 tillerson was awarded top order for foreigners from russian president vladimir putin. >> a matter of concern to me that he has such a close, personal relationship with vladimir putin. >> reporter: florida senator marco rubio blasting trump's pick. tweeting, being a friend of vladimir is not an attribute i am hoping for from secretary of state. the president-elect, again,