Pakistan's army has its own laws and courts. (Representational)

Pakistan's army has sentenced a general to life imprisonment for spying and ordered the death penalty for a brigadier and a civilian officer convicted in the same case, a military statement said on Thursday.

Following a closed-door military trial, army chief General Qamar Javed Bajwa endorsed the sentences on the three for "espionage (and) leaking sensitive information to foreign agencies in detriment to national security," the statement said.

Retired Lieutenant General Javed Iqbal was jailed for a life term, meaning he will serve 14 years in prison under Pakistani law. Retired Brigadier Raja Rizwan was sentenced to death alongside Wasim Akram, a civilian doctor employed by an army organisation.

The army did not give further details about the information that was allegedly leaked by the three men or say to whom it was disclosed. It was not clear if the two military officers had already retired from service before the case against them began.

Pakistan's army has its own laws and courts, and military officers accused of wrongdoing are always tried behind closed doors. Rulings can only be challenged or reviews in accordance with military procedures.