Greenville, SC (WLTX) - South Carolina Governor Henry McMaster and several state lawmakers are proposing a bill that would impose penalties on any city in the state that tries to become a "sanctuary city."

McMaster outlined his plans Monday morning.

"We want to be sure people are obeying the law," he said.

A sanctuary city is a municipality that limits how much it helps the federal government enforce immigration laws. That might include directing police not to question people about their immigration status if those persons are detained.

Supporters of those efforts say it helps people who are undocumented in the country come forward to report crimes and use goods and services in the city without fear of deportation. But opponents say it's a violation of federal law, and could lead to an increase in crime.

Some large U.S. cities already are sanctuary cities, but so far, no South Carolina city has announced it is a sanctuary city. McMaster wants to make sure they don't.

"Such an announcement will not be accepted," McMaster said. "We don't want that to ever happen here."

McMaster and the lawmakers say the bill that will be pre-filed would require each city to provide a sworn statement that they are in compliance with federal immigration laws and are not harboring undocumented immigrants. Cities that fail to do so would have their federal funding that is processed by the state withheld for three years.

"it is very important that we sent the word loud and clear....that South Carolina will not abide by that kind of lawlessness here," McMaster said.

The governor cited providing a safe environments for businesses to invest in South Carolina, increasing public safety, and curbing human trafficking as reasons why the measure is necessary.

"A lot of human trafficking involves alien's a network that is underground," he said.

If the law is passed, it would go into effect in 2019. The South Carolina law Enforcement Division would be in charge of certification, and he said agents here would have to work with the Department of Homeland Security to come up with a way to measure compliance.

While he admits there doesn't appear to be a problem in the state now, he says he wants to stop something before it starts.

"Fixing something after it's broken is the hard way to do it," McMaster.

The group of lawmakers say they want to put this at the front of the agency for the upcoming session.