A cash machine in Carrickmore was targeted by thieves who tried to blow it open with a gas cylinder after attempts to gain entry with a crow bar failed last Tuesday.
Police are investigating the incident, which took place on November 24.
Another ATM in Mayobridge, Co Down was also attacked in a similar way.
Police are asking the public to report any suspicious or unusual items or activity at ATMs across Mid Ulster, and indeed Northern Ireland.
Detective Chief Inspector James Mullen said: “In both incidents it appears thieves may have attempted to pump gas into the ATMs but failed in their efforts to gain entry or remove the machines.
“During the incident on Main Street in Carrickmore on 24th November thieves again attempted to remove the ATM with a crow bar.
“When this failed it appears they have attempted to pump gas from a cylinder into the machine. This also failed and they made off empty-handed.
“On 11 November thieves attempt to blow open an ATM at premises on Newry Road, Mayobridge after failing to prise it from the wall with crowbars. The ATM remained in place and the thieves left with nothing.
“This type of criminal activity obviously presents a very real risk to the community and to the businesses housing the ATMs,” he added.
“With this in mind, we are asking people to keep an eye out for anything out of the ordinary at their local cash machine.
“If a machine appears to have been tampered with, it is essential that it is reported to police. This is especially important if a hose, wires or leads of any description are visible, or if a smell of gas is noted in the vicinity.
“Please do not approach an ATM machine if a hose, wires, leads or any other unusual item is visible. Alert police immediately by calling 999.”