Bangkok(CNN) Crown Prince Maha Vajiralongkorn returned to Thailand Wednesday amid growing concerns about the health of his father, King Bhumibol Adulyadej.
The Crown Prince was seen making his way to the Siriraj Hospital, where King Bhumibol is being cared for by doctors. It's not yet known if the Crown Prince has visited the King, who remains in unstable condition, according to a Thai palace statement released Wednesday.
As the Thai nation holds an anxious vigil for their beloved King, hundreds gathered in temples and outside Siriraj Hospital. They held framed portraits of King Bhumibol and prayed for his speedy recovery. Well-wishers were dressed predominantly in pink -- an auspicious color believed to restore health -- and yellow, which is the color of the King.
Donnapha Kladbupha holds a picture of a young King Bhumibol.
"I have been coming here for 10 years since the King has been ill," Donnapha Kladbupha, a Bangkok resident and private English tutor, told CNN.
"A long time ago, the King told us he would live to 120 years [of age], but it is very difficult for him now. We still hope. He is like an angel to us and I believe he can pass this difficult time," added Kladbupha.
Outpouring of support
King Bhumibol, 88, ascended to the throne 70 years ago, making him the world's longest-reigning monarch. He is being closely monitored after undergoing medical procedures over the weekend.
With fears around the Thai King's health mounting, a government spokesman urged the Thai public to "rely on official announcements" for any updates. He added that the Thai public should not rely on "uncorroborated information in social media circles."
Thailand's King Bhumibol Adulyadej: A life in pictures
Thailand's Bhumibol Adulyadej was crowned king on May 5, 1950. News of the 88-year-old's death was announced Thursday, October 13, via a statement from the Royal Palace read on state TV. He was the world's longest-reigning living monarch.
Bhumibol, left, is pictured in 1935 with his older brother, the former King Ananda Mahidol, in Lausanne, Switzerland, where the boys attended school. King Ananda was 20 when he died of a gunshot wound under mysterious circumstances. His 18-year-old brother, known then as Prince Phumiphon Aduldet, later assumed the throne to become King Bhumibol Adulyadej.
Bhumibol and his future wife, Princess Sirikit Kityakara, are pictured in Lausanne in 1949. The couple married a year later at Srapathum Palace in Bangkok, Thailand.
The King and Queen pose with their children, Crown Prince Vajiralongkorn and Princess Ubol Ratana, on the steps of Bangkok's Chitralada Palace in 1955. Two more daughters, Princesses Maha Chakri Sirindhorn and Chulabhorn Walailak, were born in 1955 and 1957.
The royal couple ride with U.S. President Dwight Eisenhower during a five-day state visit to the United States in 1960.
The King, far right, plays the saxophone during a 1960 jam session with legendary jazz clarinetist Benny Goodman and his band in New York.
The King walks with his wife and their 13-year-old son, Crown Prince Vajiralongkorn, during a visit to Britain in 1966.
The King convenes the first meeting of his country's National Reform Assembly during a ceremony held in Bangkok in 1976. The King put the monarchy at the center of Thai society, acting as a force for community and tradition even as the country flipped between political crises and military coups.
The King raises a camera to take a photo in 1995. He was given his first camera in 1934, which ignited a lifelong enthusiasm for photography. He has often been seen with a camera around his neck during public appearances.
The King and Queen survey a rice crop made possible by a Royal Irrigation Project in 1996. The project formed part of the Royal Development Projects, which focused on developing remote rural areas. The King has taken an interest in environmental projects throughout his long reign.
The King reviews an honor guard with Queen Sirikit and Crown Prince Vajiralongkorn during the annual military parade to celebrate his birthday in 2006.
The King lights candles at a ceremony to mark Coronation Day in Bangkok in 2007.
The King is wheeled towards his yacht in 2010, during a rare public appearance to open a new flood gate and two bridges in Bangkok.
The King is pictured with family members in 2012. He addressed a crowd from a balcony on his 85th birthday.
The King is seen through a car window as he leaves the Siriraj hospital in Bangkok in 2015.
A portrait of the King is held on the eve of his 88th birthday as people gather outside the Siriraj hospital in 2015. The King of Thailand is regarded as a demi-god by many Thais, and his popularity has been viewed as a unifying force during times of political unrest.
Messages of support have been flooding social media sites, with well-wishers tweeting under the trending hashtag #LongLivetheKing.
The Crown Prince is expected to meet with Thai Prime Minister Prayut Chan-o-cha, but a government spokesman said in a statement the two would be discussing general affairs.
A group of women hold a vigil for King Bhumibol outside Siriraj Hospital.
MCOT, a Thai state-owned public broadcaster, reported a dip in stocks trading Wednesday, with Thailand's main index hitting its lowest rate since May 2016. The slight market tumble suggests mounting uncertainty around the King's health.
Thai citizens, however, remained adamant that their prayers would help the King recover.
A woman prays for King Bhumibol's speedy recovery outside Siriraj Hospital.
Thai businessman Sira Singsat, 24, joined the vigil held for the King outside Siriraj Hospital with his mother and sister. He praised the King, calling him a "role model" for the Thai people and a "spiritual leader."
"I have come here to pray. We believe that this will help him to recover," he told CNN. "I guess we are a little bit worried about what happens next, but it is important now to support and pray for our King."
Journalist Patrick Sarnsamak contributed to this report.