LONDON, June 6 (AFP) - Queen Elizabeth II on Sunday brought the curtain down on her historic Platinum Jubilee celebrations, making another public appearance on the last of four days of festivities and vowing to maintain her record-breaking reign.

The 96-year-old monarch, who has been troubled by mobility problems, appeared for the first time in person since Thursday on the Buckingham Palace balcony after the Trooping the Colour military parade.

Her exertions at the start of the celebrations had forced her to pull out of a thanksgiving church service on Friday, plus the Epsom Derby horse race and a star-studded concert on Saturday.

Huge crowds stretching hundreds of metres down The Mall outside the palace cheered as she re-emerged onto the balcony briefly on Sunday afternoon.

It followed a public parade reflecting changes in music, dance, fashion, culture and society since she came to the throne in 1952.

Dressed in green with a matching hat, her white gloved hand clutching a walking stick, she was flanked by the three future kings: Princes Charles, William and George.

In a statement issued shortly after, the monarch said she had been "humbled and deeply touched" by the turnout for her Platinum Jubilee celebrations and "inspired by the kindness, joy and kinship that has been so evident in recent days".

Britain's longest-serving sovereign added: "While I may not have attended every event in person, my heart has been with you all; and I remain committed to serving you to the best of my ability, supported by my family".