MIAMI (AP) — Miami International Airport is closing a terminal this weekend because security screeners have been calling in sick at twice the airport's normal rate as the federal government shutdown stretches toward a fourth week.

Friday marks the first day screeners will miss a paycheck, and airport spokesman Greg Chin said there's a concern there won't be enough workers to handle all 11 checkpoints during normal hours over the weekend.

Related: Government shutdown: TSA agents continue to work without pay

Chin said Terminal G will close at 1 p.m. Saturday, reopen for flights Sunday morning and close again at 1 p.m. that day. The terminal serves United Airlines along with smaller carriers. Its closure means restaurants and shops that depend on departing flights also will close.

"We felt we had to make a decision before the weekend," Chin said. "They're erring on the side of caution."

Read: Here's a list of agencies that are open during the partial government shutdown

Chin told The Miami Herald that some passengers have complained about longer waits, but there've been no abnormal security delays.

Terminal G is the slowest concourse at the airport, with about 12 planes a day flying out after 1 p.m. That's about 3 percent of the roughly 450 flights that depart each day. Terminal G's flights will be diverted to other terminals this weekend.

But Chin said that if the shutdown continues and additional screeners don't show up for work, the airport could be forced to close a security checkpoint at terminals that have multiple entry points, such as Concourse J or Concourse D.