Jordan 'hits limit' hosting Syrian refugees
"Jordan has reached the limit of its capacity to cope with the burden of hosting Syrian refugees," Planning Minister Imad al-Fakhoury said in a statement after meeting Haley.
Syria's six-year conflict has triggered a vast exodus of refugees, millions of whom are living in neighbouring states.
The UN refugee agency says it has registered more than 680,000 Syrian refugees in Jordan.
Amman says it hosts some 1.3 million Syrians at a cost of some $6.6 billion (5.9 billion euros) since the war broke out in 2011.
Jordan says it will need a further $8 billion to cover the costs of hosting refugees until 2018
Haley also met Jordan's King Abdullah II Monday as part of a trip focused on the plight of Syrian refugees in Jordan and Turkey.
On Sunday she visited Jordan's Zaatari camp which hosts some 80,000 refugees displaced by the conflict in neighbouring Syria.
She tweeted that she wanted to "see first-hand how the Syrian crisis is affecting children."
Her first field visit comes as UN agencies worry about proposed US funding cuts that could cripple the world body's humanitarian work.
The State Department says it has donated $6.5 billion in aid since the Syrian conflict began.
But President Donald Trump sparked a global uproar earlier this year by suspending a US resettlement program for refugees from Syria.
Haley said last week that the US administration would continue to support countries on the front line of the refugee crisis.
According to the UN children's agency UNICEF, 2.3 million Syrian children are living as refugees in Turkey, Lebanon, Jordan, Egypt, and Iraq.