He said the former crown prince had been "asked to stop some activities that could be used to shake the stability and security of Jordan".
Saudi Arabia on Saturday said that it is standing by Jordan, stressing full support for all measures and decisions taken by His Majesty King Abdullah and HRH Crown Prince Hussein to maintain security and stability.
"Jordanian citizens, Hassan bin Zaid, Basem Ibrahim Awadallah, and others were arrested", Sputnik reported citing sources.
Prince Hamza said in a video recording he was under house arrest and had been told to stay at home and not contact anyone.
Through the video Prince Hamzah denied any wrongdoing and said he was not part of any conspiracy. "Unfortunately, this country has become stymied in nepotism, in corruption, and in misrule and the result has been the destruction or the loss of hope that is apparent in pretty much every Jordanian", he said.
Two people familiar with the situation told Reuters security forces had arrived at his small palace and begun an investigation.
The country's top general had earlier denied that Hamzah - a former crown prince who was stripped of the title in 2004 - was arrested or under house arrest, even as authorities announced the arrests of former senior officials close to the ruling monarchy.
A former USA official with knowledge of the events in Jordan said the threat did not involve a physical coup.
It reportedly comes after the prince made a visit to tribal leaders where he is said to have garnered support.
Jordan would investigate whether there was a foreign hand in the plot, said the former US official.
Prince Hamza, the half-brother of Jordan's King Abdullah, says he has been placed under house arrest by Jordanian authorities and accused the country's leadership of corruption and incompetence. The authorities had cracked down on several demonstrations, detaining dozens.
What other countries are expressing solidarity with King Abdullah?
What do we know so far?
In late March, media reported that Jordanhad unveiled a new defense agreement with the U.S., which allowed free entry of American military personnel, aircraft and vehicles into the Kingdom.
King Abdullah has received statements of support from Egypt, Lebanon, Bahrain, Saudi Arabia, the Gulf Cooperation Council and the United States.
Ned Price, a spokesman for the US State Department, said: "We are closely following the reports and are in touch with Jordanian officials".
Arrests by senior officials and members of the royal family are rare in Jordan, considered one of the most stable Arab countries.
As the eldest son of Queen Nour (nee Lisa Halaby), his father's fourth and final queen, the now-41-year-old prince was thought to be King Hussein's top choice as successor; he was passed over because he was still in school.
He has criticized the government in the past, accusing officials of "failed management" after they approved an income tax law in 2018.
Another suspicious name is that of Bassem Awadallah, a former finance minister, a former advisor to King Abdullah II and a close figure to the Saudi prince Mohammed bin Salman.
The Jordanian Hashemite dynasty's tradition under the 1952 constitution gives the succession to the eldest son but the monarch retains the option of naming a brother.
Egyptian mummies move to new home
The National Museum of Egyptian Civilisation was completed in 2010, and Hawass said he had planned to open it in 2012. The government is hoping that the grand parade of mummies will help to attract tourists and revive the industry.
Suspect in U.S. Capitol attack suffered delusions
This story has been corrected by referring to Louis Farrakhan as the Nation of Islam's longtime leader, not its founder. The attack came months after the January assault on Congress by hundreds of supporters of then-president Donald Trump.