The foreign ministry made the move on Tuesday, a day after its spokesman Maciej Wewiór said Poland would also query Budapest, asking what documents allowed Ziobro to cross borders and enter the US after his Polish passports were annulled.
The State Department has declined to say what visa, if any, Ziobro used to enter the country, citing the confidential nature of visa records.
In a brief statement to Polish Radio, a spokesman said only that the US and Poland share "close political, economic and social ties rooted in centuries of friendship".
The White House also declined to comment.
Ziobro's lawyer says he entered on a so-called Geneva travel document – issued to those recognised as refugees – which does not carry visa-free access to the United States.
Meanwhile, Marcin Przydacz, head of the presidential International Policy Bureau, confirmed on Tuesday that Ziobro's case had not come up in any of Polish President Karol Nawrocki's meetings with US leader Donald Trump.
"I was present at all the conversations and the topic did not arise once," he said.
Przydacz suggested the situation reflected poorly on Poland's justice system, saying there was no certainty it operated "in a truly independent manner".
He added that, as a lawyer, he believed everyone had the right to defend themselves as they saw fit.
Ziobro, a senior Law and Justice (PiS) politician, announced on Sunday he had left Budapest, where he had been granted international protection by Hungary, and was now in the US.
Prosecutors want to bring 26 charges against him over alleged irregularities in the Justice Fund, a state scheme aimed at supporting crime victims.
(ał)
Source: PAP, IAR