Two children hold the Union flag as they prepare to leave flowers outside the gates of Buckingham Palace in London, a day after the death of Britain's Prince Philip, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (AP Photo/Alberto Pezzali)

A woman places tape on a note to leave outside the gates of Buckingham Palace in London, a day after the death of Britain's Prince Philip, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (AP Photo/Alberto Pezzali)

People wait in line to leave flowers and notes outside the gates of Buckingham Palace in London, a day after the death of Britain's Prince Philip, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (AP Photo/Alberto Pezzali)

People gather outside the gates of Buckingham Palace in London, a day after the death of Britain's Prince Philip, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (AP Photo/Alberto Pezzali)

Members of the 104th Regiment Royal Artillery fire a 41-round gun salute in the grounds of Cardiff Castle, to mark the death of Prince Philip, in Cardiff, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (Ben Birchall/PA via AP)

Members of the 104th Regiment Royal Artillery fire a 41-round gun salute in the grounds of Cardiff Castle, to mark the death of Prince Philip, in Cardiff, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (Ben Birchall/PA via AP)

Members of the 104th Regiment Royal Artillery fire a 41-round gun salute in the grounds of Cardiff Castle, to mark the death of Prince Philip, in Cardiff, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (Ben Birchall/PA via AP)

People gather around the Queen Victoria Memorial near Buckingham Palace in London, a day after the death of Britain's Prince Philip, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (AP Photo/Alberto Pezzali)

This undated photo released Saturday, April 10, 2021 by Novaya Gazeta, shows Roman Anin, chief editor of the Vazhnikh Istorii website pose for a photo in Moscow, Russia. Authorities searched the apartment of a prominent Russian investigative journalist and took him in for questioning, apparently in connection with a story about one of President Vladimir Putin's closest associates, his lawyer and publication said Saturday. (Novaya Gazeta via AP)

Members of the 104th Regiment Royal Artillery fire a 41-round gun salute in the grounds of Cardiff Castle, to mark the death of Prince Philip, in Cardiff, Saturday, April 10, 2021. Britain's Prince Philip, the irascible and tough-minded husband of Queen Elizabeth II who spent more than seven decades supporting his wife in a role that mostly defined his life, died on Friday. (Ben Birchall/PA via AP)