A former adviser to Jordan’s King Abdullah and a member of the royal family are among a number of people arrested on “security-related” grounds.
Bassem Awadallah, a former finance minister, and Sharif Hassan Bin Zaid, a royal, were detained.
The military denied reports the king’s half-brother, former Crown Prince Hamza bin Hussein, was among those arrested.
But it said he had been ordered to stop actions that could be used to target the country’s “security and stability”.
High level political arrests are rare in Jordan, a key US ally in the Middle East.
The country has a powerful intelligence agency that has been granted new powers since the coronavirus pandemic, which has drawn criticism from rights groups.
Mr Awadallah, an economist who was educated in the US, has been a confidant of the king and an influential force in Jordan’s economic reforms.
He has often found himself pitted against entrenched government bureaucracy resistant to his reforms.
Petra news agency earlier said the former Crown Prince Hamzah bin Hussein, the oldest son of the late King Hussein and Queen Noor, was not subject to any restrictions.
However, in a later statement the military said he had been asked to stop any actions targeting the country’s security and stability.
It was seen as a blow to Queen Noor, who had hoped to see her eldest son become king.
Prince Hamzah, who was 24 at the time, had been a favourite of the late King Hussein, who often described him in public as the “delight of my eye”.
However, he was seen as too young and inexperienced to be named successor at the time of his death.
Jordan is a key US ally and has assisted US forces in security operations. It is also a partner in the US-led campaign against the so-called Islamic State.
The country has few natural resources and its economy has been hit hard by the pandemic. The kingdom has also absorbed waves of refugees from the civil war in neighbouring Syria.