The two-term premier, whose bid to stay in power has faltered, urged security personnel "to stay away from the political crisis and continue in their security and military duties to defend the country," a statement on Maliki's website said.
Maliki is the commander in chief of the armed forces.
UN Iraq envoy Nickolay Mladenov on yesterday warned Iraq's military against political interference, after special forces, police and soldiers deployed around strategic installations in Baghdad.
Despite Maliki railing against Abadi's selection as a "constitutional violation," his rival has gained widespread international support, most importantly from Washington and Tehran.