Foreign secretary Dominic Raab said 'Russian actors' almost certainly tried to amplify sensitive leaked documents.
The Labour leadership contender said he wanted a new constitutional set-up 'based on federalism'.
Phillips dropped out of the race to succeed Jeremy Corbyn but is backing the Edinburgh South MP for deputy.
The shadow business secretary says independence would be for the people of Scotland to decide.
Scotland's only Labour MP has launched a bid to become the deputy leader.