Japan's House of Representatives released a message on Tuesday, congratulating Emperor Akihito's 30-year reign ahead of his abdication at the end of April, the first such message for a specific imperial anniversary.

"We, the Japanese people, respectfully acknowledge His Majesty the Emperor's achievements over the past 30 years under his era of Heisei, during which he has always stood by the people and prayed for their peace," the message said.

Japan's House of Councillors, or upper house, is also planning to release a separate message regarding the emperor, according to local media reports.

Japan held a ceremony commemorating 30 years of the emperor's reign in Tokyo on Sunday. Prime Minister Shinzo Abe attended the ceremony and said in a speech that the Japanese will "never forget" how the imperial couple have "always stood by the people for 30 years."

Emperor Akihito said it is "fortunate that I have been able to undertake duties with the help of people," adding that he thanks "the people, in whom I take pride and for whom I feel joy in being 'the symbol of the state' and the civilization of this country built over the long period."

Emperor Akihito, 85, was enthroned on Jan. 7, 1989, starting the Era of Heisei. In a rare nationally-televised address in August 2016, he expressed his desire to relinquish his duties as emperor owing to concerns about his age, health and ability to carry out his formal duties.