Senate Majority Whip John Cornyn plans to introduce a border security bill Thursday that would extend the southwestern border wall and boost interior enforcement of the nation's immigration laws, including through a so-called sanctuary city provision.

"We are going to have some legislation that provides a plan that deals not just with individual pieces of infrastructure but a border-wide plan that involves a lot of work from both sides of the aisle and both sides of the Capitol," Cornyn, R-Texas, told the Washington Examiner.

Cornyn collaborated on his legislation with House Homeland Security Committee Chairman Michael McCaul, R-Texas, but the two have produced different bills.

McCaul introduced legislation last week that deals only with border security and does not address interior enforcement. It does not include a sanctuary city provision, which would restrict federal funding cities that do not comply with federal immigration laws. The House this summer passed such a measure in separate legislation that has not been considered in the Senate.

The McCaul bill authorizes $10 billion for a southern border wall and technology to combat illegal immigration, adds $5 billion for targeting illegal ports of entry and would add 10,000 customs and border patrol agents.

In addition to the sanctuary city provision, Cornyn's legislation would prohibit children from being released to illegal immigrant adults if they crossed the border illegally and were picked up by border agents. Children could be released only to adults living lawfully in the United States.

Republicans have long been critical of the U.S. policy of releasing illegal minors into the United States.

A GOP-led Senate investigation last year accused the U.S. Office of Refugee Resettlement of failing to conduct background checks into the adults picking up the minors, which in some cases lead to abuse by traffickers.

Cornyn's proposal has earned initial support from the Federation for American Immigration Reform, which advocates for reduced immigration.

But FAIR Director of Government Relations Robert Law said he has little hope it would make it past filibuster by the Democrats if it received a Senate vote this year.

"At this point, it doesn't look like any enforcement bill could pass the Senate," Law said. "Because Democrats are bonding together on any measure that enforces our immigration laws."