BANGKOK, Dec. 5 — Thai Prime Minister Abhisit Vejjajiva on Sunday evening led people across the country in lighting candles to celebrate King Bhumibol Adulyadej’s birthday.

Hundreds of illuminating boats decorated with elaborate light bulbs lit the main Chao Phraya River in Bangkok into colorful light in an extravagant show of loyalty to the revered king.

Hundreds of fireworks brightened the night sky of Bangkok after Abhisit led cabinet ministers, government officials, military officers and ordinary citizens to sing the royal anthem.

Later in the evening, the premier led another singing of the royal anthem from a riverside stage with thousands of lit lanterns floating in the sky, which could be viewed from the hotel where the king is staying.

Seven films showing the king’s various initiations in social and economic development were also inaugurated, with hundreds of thousands of copies of the movies to be distributed for free to the public.

These were parts of a series of celebrations organized by the Thai government and private sector, which started on Dec. 1 and will continue until Dec. 9, to celebrate the occasion.

King Bhumibol, the longest-serving head of state in the world, turned 83 on Sunday.

He has been staying in Siriraj hospital in Bangkok since September 2009, but had made public appearance occasionally.