Mark Kelly pays tribute to John McCain as he’s sworn into US Senate

Former astronaut Mark Kelly was sworn into the US Senate after visiting the grave of his hero John McCain.

Mr Kelly, a Democrat who will serve out the remainder of Mr McCain's term until 2023, was joined by his wife and daughter as the family paid respects at the late Republican's gravesite at the US Naval Academy Cemetery.

"Senator McCain has been a hero of mine since I was a young pilot. He left a legacy of service to Arizona and country that can't be matched, but that we should all strive towards," Mr Kelly said in a tweet.