US President Joe Biden declared his support for Jordan in a call to King Abdullah II on Wednesday, days after Jordan said it had foiled an operation by dissenters to destabilise the country.
Mr Biden stressed the importance of King Abdullah's leadership to the US and the region, the White House said.
The president also affirmed his country's support of a two-state solution to the Israeli-Palestinian conflict, a return to the long-standing US position prior to the Trump administration.
On Thursday, US Secretary of State Antony Blinken also spoke to King Abdullah to commend him "for Jordan's steadfast leadership promoting peace and stability in the Middle East", a State Department spokesman said.
The US this week said it would provide $235 million in funding for Palestinians that former president Donald Trump cut off, including $150m for the UN Relief and Works Agency for Palestinian refugees (UNRWA).
Blinken has said US assistance to the Palestinians "serves important US interests and values" and "provides critical relief to those in great need".
The organisation also fosters economic development and supports Israeli-Palestinian understanding, security co-ordination and stability, Mr Blinken said.
In his first public address since Jordan said it had arrested 16 people on "security charges", King Abdullah said on Wednesday that sedition in his country had been "nipped in the bud".
Among those arrested were royal family member Sharif Hassan ben Zaid and the former chief of the royal court, Bassem Awadallah. Former crown prince and the king's half-brother Prince Hamzah bin Hussein said he was placed under house arrest.
“Nothing and no one comes before Jordan’s security and stability, and it was imperative to take the necessary measures to honour that responsibility," King Abdullah said.
He said the issue was personally taxing for him given Prince Hamzah's relationship to the royal family.
"Sedition came from within and without our one house, and nothing compares to my shock, pain and anger as a brother and as the head of the Hashemite family, and as a leader of this proud people," the king said.
Prince Hamzah issued a letter backing the king and pledging his loyalty to him. He has not been arrested.
“Hamzah is today in his palace, with his family, under my care,” King Abdullah said.
Mr Biden's relationship with King Abdullah began with the monarch's ascension to the throne in 1999.
After his election victory in November, President Biden's first call to the region was to the Jordanian king.
US-Jordanian relations declined during Mr Trump's term, in part because of his non-committal stance on a two-state solution.
Under Mr Biden, the US has indicated it would help Jordan to support its 1.4 million refugees, who make up more than 10 per cent of the population.
The US government also authorised military sales to the kingdom, including F-16 fighter jets in February, and last month signed a new defence agreement with Jordan allowing US forces to carry weapons while stationed there.
Despite renewed US support, UNRWA said it still faces a shortfall of about $150m in its 2021 budget.