This is stated in an interview with Michael Carpenter for Delfi.
"We have long believed that what our allies supply is their business. And we support the countless contributions that our allies have made to Ukraine... And so I expect there will be broad support in the United States for our allies to continue to increase their contributions," the US Ambassador to the OSCE said.
When asked if the above statement was about F-16 fighters, the ambassador confirmed.
As a reminder, the Dutch Cabinet of Ministers will consider supplying Ukraine with F-16 fighter jets and paying for Leopard 2 tanks.