(CNN) An attempt by two Australian inmates to tunnel out of a prison cell, using toothpaste and toilet paper to conceal their escape, has been foiled by authorities
The two inmates at the Bathurst Correctional Center, an all-male medium-security prison west of Sydney, had planned to escape detection by using toothpaste to glue down toilet paper to conceal any signs of digging.
But a corrections officer noticed the damaged mortar at the back of the cell during a routine search of the cell Thursday, and decided to investigate.
"I noticed near the cell bars at the back of the cell what appeared to be diggings into the concrete, and the mortar had been removed from around the large sandstone block," the officer said in a statement by the New South Wales (NSW) Justice Department on Thursday.
"A flag shape had also been painted onto the sandstone block to disguise the damage," she added.
The mortar was dug out of an area 17.7 inches (45 cm) across by 11 inches (28 cm) down, in some places as deep as 7 inches (18 cm) into the wall.
The inmates, who denied all knowledge of wrongdoing, have been placed in segregation while the police continue to investigate.
Corrective Services NSW Commissioner Peter Severin praised the officer's "curiosity and methodological cell search" in the press release, and said escape attempts would always be uncovered by his officers.
"I also wish to thank this officer for reminding inmates that these types of attempts -- particularly in a medium-security centre - are futile. Our officers are well-trained and good at what they do," he said Thursday.
The number of prison jailbreaks have declined in NSW jails in recent decades, according to the state's Justice Department.
Only ten prison inmates escaped from prisons across NSW last year, compared to 183 escapes more than three decades ago in 1983-1984.