HAMILTON, Canada

Some US airports could be forced to close if a government funding crisis continues, a senior US airport security official warned on Tuesday.

Adam Stahl, a top official at the Transportation Security Administration (TSA), told Fox News that staff reserves have run out amid a partial government shutdown that has left workers unpaid.

"We have a national deployment office force, and we've fully depleted that. So, at this point, we're fully stretched," said Stahl.

"If this continues, it's not hyperbole to suggest that we may have to quite literally shut down airports, particularly smaller ones, if call-out rates go up," he added.

Stahl urged lawmakers to quickly resolve the standoff, warning of "significant pain" ahead for air travelers if no agreement is reached.

As the shutdown continues, Senate Democrats have sought to pass narrower bills to fund certain agencies within the Department of Homeland Security, including the TSA and the Federal Emergency Management Agency (FEMA), along with other agencies not linked to immigration enforcement, but Senate Republicans have rejected the effort.