Huge crowds in the Vatican cheered Pope Benedict XVI on Wednesday as he made his first public appearance since announcing his resignation at the end of the month.

He thanked the Roman Catholic faithful in several languages and said it was not appropriate for him to continue as pope.

"I've decided to resign the ministry given to me by the Lord. I've done this in full freedom, for the benefit of the Church," he told those gathered in a Vatican City audience hall for his regular weekly appearance.

Benedict said he was fully aware of the gravity of his decision but that he could not carry on as pope "if I don't have the strength that it requires."