Senate Minority Leader Harry Reid launched a petition on Monday pressuring Donald Trump to prove he can pass the U.S. citizenship test.

The petition said Trump should "put up or shut up" about immigration until the GOP presidential nominee can show his knowledge of the country he intends to lead.

"Donald Trump wants to impose new tests for immigrants coming to America," read the petition. "Immigrants already face vigorous testing before gaining citizenship. And before Donald Trump makes it even harder for these hardworking people to achieve their American Dream, he should prove he can pass the test himself."

Reid said last week that Trump would fail the current naturalization requirements, let alone the more stringent ones Trump has previously said he would favor, describing him as a "spoiled, unpatriotic drain on society who has earned nothing and helped no one."

Trump has asserted that he is working with the Hispanic community to ensure fair but firm naturalization policies, which has led to some criticism from conservatives that Trump may be softening his hardline approach for dealing with millions of illegal immigrants.

"No. I'm not flip-flopping. We want to come up with one a really fair, but firm answer. That's — it has to be very firm. But we want to come up with something fair," Trump said.