All fingers are pointing to Russia as the source of the worst-ever hack of US government agencies. But President Donald Trump, long wary of blaming Moscow for cyberattacks, has so far been silent.

The lack of any statement seeking to hold Russia responsible casts doubt on the likelihood of a swift response and suggests any retaliation - whether through sanctions, criminal charges or cyber actions - will be left in the hands of President-elect Joe Biden-s incoming administration."I would imagine that the incoming administration wants a menu of what the options are and then is going to choose," said Sarah Mendelson, a Carnegie Mellon University public policy professor and former US ambassador to the UN-s Economic and Social Council.