Jordan's Prince Hamza pledged allegiance to King Abdullah II on Monday as the monarch accepted mediation over a rift within the royal family that saw the prince placed under house arrest, the palace said.
The government has accused Hamza, an ex-crown prince and half-brother of King Abdullah, of a "wicked" plot and involvement in a seditious conspiracy to "destabilize the kingdom's security".
Hamza, detained along with at least 16 others, had earlier struck a defiant tone saying he had been placed under house arrest inside his Amman palace, but insisting he would not obey orders restricting his movement.
But in an apparent easing of the palace turmoil, the 41-year-old prince pledged his backing to King Abdullah.
"I will remain... faithful to the legacy of my ancestors, walking on their path, loyal to their path and their message and to His Majesty," he said in a signed letter, quoted by the palace.
"I will always be ready to help and support His Majesty the King and his Crown Prince," he is quoted as writing.
Hamza's statement came shortly after the palace said Abdullah had agreed to enter mediation "to handle the question of Prince Hamza within the framework of the Hashemite (ruling) family".
The job of mediator was handed to his uncle, Prince Hassan, himself a former heir to the throne.
King Abdullah, 59, named Hamza crown prince in 1999, in line with their father's dying wish, but later stripped him of the title and named his own son Prince Hussein heir to the throne.
Washington, Gulf countries, Egypt and the Arab League have all pledged support for King Abdullah, and a similar message came from Russia on Monday.
US State Department spokesman Ned Price on Monday reiterated Washington's backing of Abdullah.
"We value his integrity, his vision," Price told reporters. "The king has our full support."
"This sedition was nipped in the bud," Foreign Minister Ayman Safadi said Sunday, charging the plotters had linked up with foreign parties.
Safadi declined to identify the alleged foreign parties, but he said an individual "with links to foreign intelligence services" had offered to fly Hamza's wife out of the country.