With Trump, a bitter NAFTA critic, seated in the front row, Mulroney hailed the "largest and richest free trade area in the history of the world." The three countries have agreed on a revised trade agreement pushed by Trump.

Earlier, a military band played "Hail to the Chief" as Bush's casket was carried down the steps of the US Capitol, where he had lain in state. Family members looked on as servicemen fired off a cannon salute.

His hearse was then driven in a motorcade to the cathedral ceremony, slowing in front of the White House, the route lined with people much of the way, bundled in winter hats and taking photos.

Waiting for his arrival inside, Trump shook hands with Obama and former first lady Michelle Obama, who greeted him by saying "Good morning." Trump did not shake hands with Bill and Hillary Clinton, who looked straight ahead.

Bill Clinton and Mrs. Obama smiled and chatted as music played. Carter was seated silently next to Hillary Clinton in the cavernous cathedral. Obama cracked up laughing at someone's quip. Vice President Mike Pence shook Carter's hand.