His son, the crown prince, returned home from Germany, as Thais in pink shirts — a color associated with the king — gathered outside Siriraj hospital in Bangkok, which has been his home for much of the last decade.

The royal palace said in a statement late Wednesday that the 88-year-old king's blood pressure had dropped, his liver and kidneys were not working properly and he remained on a ventilator. "His majesty's overall condition is still unstable," it said.

Dozens of Thais holding incense sticks and images of the king chanted prayers outside the hospital for his recovery.

"The king is the heart of our country. So, without a heart, we cannot survive. So we pray for our heart, for the heart of our land," said Donnapha Kladbupha, a 42-year-old English tutor. "I want to see him come and say hello to the Thai people again."

Thai stocks have slid daily since Sunday, when the royal palace announced that Bhumibol's condition was unstable, the first time it has used that phrase regarding the king's health.

On Wednesday, the Stock Exchange of Thailand's benchmark fell nearly 7 percent in afternoon trading before recovering somewhat for a 4.1 percent loss for the day. The Thai baht fell 1.1 percent to end at 35.76 to a dollar.

The highly revered Bhumibol, the world's longest-reigning monarch, has suffered from a variety of ailments related to old age, including kidney and lung problems.

(Read also: Anxious Thais don pink for ailing King Bhumibol)

Last week, doctors performed a hemodialysis to purify his blood. They also replaced a tube that drains excess cerebrospinal fluid.

Because Bhumibol has been king since 1946, there is great concern about the eventual succession. Crown Prince Vajiralongkorn has not earned the same respect as his father.

Vajiralongkorn lives mostly in Germany, and flew back to Bangkok. The government's top bureaucrat, Secretary-General Wilas Aroonsri, said Prime Minister Prayuth Chan-ocha went to the airport to receive him. Prayuth was supposed to fly to Laos on an official visit but canceled it in the morning.

Bhumibol, a constitutional monarch with no formal political role, is widely regarded as Thailand's unifying figure. However, as his health has deteriorated, his participation in public affairs has sharply declined in recent years.

Concern about succession has been entwined with Thailand's political turmoil in the past decade, as royalists have sought to ensure that they control the process instead of certain politicians whose fealty to the monarchy they doubt.

In Washington, Daniel Russel, the top U.S. diplomat for East Asia, described Bhumibol — who was born in the U.S. and visited twice in the 1960s — as "a true friend of the United States."

"We wish the best in terms of the health of the Thai king. He's a revered figure in Thailand and he's an admired figure in the United States. We hope his situation will stabilize," Russel told reporters Wednesday.

___

Associated Press journalists Kiko Rosario in Bangkok and Matthew Pennington in Washington, D.C., contributed to this report.

Popular

Women in philanthropy: Fifi Pangestu’s leadership and vision in Bakti Barito Foundation

Philippines to endure extreme heat until mid-May

Magnitude 6.5 earthquake strikes off Java island: authorities