WASHINGTON (AP) — A senior House Republican said Thursday that it's impossible to "defund" President Barack Obama's upcoming moves on immigration in an upcoming spending bill.

Appropriations Committee Chairman Harold Rogers, R-Ky., said the Citizenship and Immigration Services agency gets its money through application fees, so Congress can't stop it by withholding funding in a spending bill.

A temporary government funding bill expires next month, and some conservative Republicans want to use a must-pass spending bill to block Obama on immigration. They argue that Republicans should consider every option, including using Congress' power of the purse, to stop Obama's upcoming executive order that would effectively permit almost 5 million undocumented immigrants to remain in the country.

A similar effort last year to block a part of the national health care law led to a 16-day government shutdown.

"The agency has the ability to continue to collect and use fees to continue current operations, and to expand operations as under a new executive order, without needing legislative approval," said Jennifer Hing, a spokeswoman for Rogers.

Next month's spending bill could still carry legislative language unrelated to funding the immigration agency that's designed to thwart Obama on immigration. Last year, for instance, House Republicans linked a short-term spending bill to legislation requiring a one-year delay in the requirement that everyone buy health insurance under the Affordable Care Act. The result was a lapse in funding that shuttered nonessential federal agencies.