Melaka police chief Datuk Chuah Ghee Lye said at least two persons were believed responsible in the incident which occurred about 2 am and the police were investigating to ascertain the amount of money missing from the machine.
"Another bomb did not explode and we are checking if it was used for backup or left behind.
"We are analysing the bomb to identify its type and the culprits involved," he told reporters here.
Chua said initial investigations revealed that the culprits were experts.
"The way they (suspects) place the bomb show they have the expertise. Prior to this, there have been attempts (use bombs), but (bomb) did not tear the machine," he added.
He said instruction had been issued to all district police chiefs to step up patrol in their respective areas to avoid a similar incident.
On the bomb that was found at the scene, Chuah said police exploded it at 10.25 am as a safety measure.
The police detonated another bomb which did not explode and left at the scene at 10.25am. -Pix by PDRM
He said the police would view footage of closed-circuit television (CCTV) recordings in the vicinity to identify individuals and vehicles entering and leaving the ATM premises.He urged those with information on the incident to contact the police.
Meanwhile, Melaka Tengah district police chief ACP Shaikh Abdul Adzis Shaikh Abdullah said initial investigation revealed that a pipe bomb was used to rip open the ATM machine.
"The second bomb that was found was still active and believed to have misfired in the incident," he added.
He said police believed at least two persons were involved in the act.
Police have also taken measures to ensure the premise is now safe, he added.