MANILA — President Rodrigo Duterte’s declaration of a “state of lawlessness” in the Philippines after a blast that left at least 14 dead raised fears on Saturday that it could lead to a curtailment of basic freedoms.

The declaration of a state of lawlessness would allow the military to carry out some police operations, including patrolling urban areas, conducting searches, enforcing curfews and setting up checkpoints, Mr. Duterte said.

A presidential spokesman, Ernesto Abella, said Saturday that the declaration was “limited” and allowed for the use of troops only to deal with security threats and to “suppress” violence.

Mr. Abella emphasized that the president was not declaring martial law, which he could do only in response to an “invasion or rebellion, and when the public safety requires it.”