Seven inmates were still on the run Sunday after a stunning jailbreak in the southern US state of Louisiana that took hours to be detected, placing tourist hub New Orleans on high alert.

Three other men have been captured since their early Friday morning escape, which authorities suspect may have been facilitated by jail staff.

Surveillance video released by the sheriff's office shows the men forcing open a cell door shortly after midnight and later sprinting out of the building through a loading dock. They then scaled a perimeter wall, using bedding to protect themselves from barbed wire.

A photo from inside one cell shows a large hole in the wall where a metal toilet had been removed. Written above the hole are messages saying, "we innocent," "we out" and "to (sic) easy LOL."

It wasn't until a routine headcount at 8:30 am that their absence was revealed.

With such a big head start, the escapees could have gone "frankly anywhere across the country," Louisiana Attorney General Liz Murrill said on Friday.

But one detainee was quickly arrested on Friday morning, hiding under a car in a hotel parking lot in New Orleans' historic and busy downtown area. Two others were captured later in the day.

The sheriff's office on Friday had outlined significant deficiencies in the prison.

"In addition to defective locks on the cells, approximately one-third of the security cameras throughout the facility are currently inoperable, including three cameras in the unit from which the escape occurred," the office said in a statement.

The FBI is offering a $5,000 reward for information leading to the arrest of any of the inmates, saying they "should be considered armed and dangerous."