Although there is no official announcement, some credible sources claim that the US Congress declared June 8 as National Best Friends Day in 1935.
https://www.hindustantimes.com/lifestyle/festivals/national-best-friends-day-2023-best-wishes-whatsapp-messages-quotes-facebook-status-to-share-with-your-best-pals-101686029947458.html
The International Day of Friendship is a United Nations (UN) day that promotes the role that friendship plays in promoting peace in many cultures. It is observed on July 30 each year.