Hillary Rodham Clinton struggled to fit into the government of President Barack Obama after being appointed Secretary of State in 2009, according to emails released by the State Department on Tuesday.

They showed Clinton turning up for meetings that had been canceled and worrying about how much time she had with her new boss, revealing growing pains in the relationship between her and former election rival Obama in the early months of her time as America's top diplomat.

In an email to two aides on June 8, 2009, Clinton was unsure if the White House had held a Cabinet meeting and whether she should attend.