US President Barack Obama has pledged to Jordan an additional $200m (£131m) to help deal with the growing number of Syrian refugees in the country.
After talks in Amman, Mr Obama said the funds - if backed by Congress - would help provide more humanitarian aid.
Some 450,000 Syrians have fled to neighbouring Jordan since the unrest began in 2011, putting huge pressure on the Jordanian authorities.
Meanwhile, Jordan's King Abdullah ruled out closing Jordan's border with Syria.
President Obama said he would ask Congress to provide additional funds as "budget support" to help the Syrian refugees.
He said this would help improve basic services at refugee camps along the Jordan-Syria border.
The US is already the largest single donor of humanitarian assistance to Syrian refugees.
The number of Syrians who have fled the country to escape the conflict between the government and rebel forces reached one million earlier this month, according to the UN High Commission for Refugees.
The UN says half of those leaving Syria are children, most of them under 11 and often traumatised by their experiences.
Along with Jordan, the many Syrians are seeking shelter in Lebanon, Turkey, Iraq and Egypt.