ISLAMABAD: A Lahore court has issued a death warrant for a schizophrenic man, his lawyers said, months after the Supreme Court had halted the execution of another mentally-ill prisoner.

Lahore jail authorities pressed ahead with seeking the death warrant of Khizar Hayat, which was granted by a sessions court, and the execution has been set for January 17.

Khizar Hayat, a 55-year-old former police officer, was sentenced to death in 2003 for shooting a colleague.

The United Nations has previously called on Pakistan to protect mentally-ill inmates, singling out Hayat as having "psycho-social disabilities".

The Justice Project Pakistan (JPP), which is managing his case, said Hayat´s lawyer in September 2015 had challenged the execution in light of his mental illness.

Hayat was diagnosed by government doctors in 2008, when a de facto moratorium on the death penalty was in place.

Another mentally-ill man, Imdad Ali, was given a last-minute reprieve from execution by the Supreme Court in October, which said it was "inappropriate" to hang someone in his condition. A final decision on his fate remains pending.

"Expert medical opinion and Pakistan´s international obligations makes Khizar´s execution not only unlawful but also inhumane," said Sarah Belal, executive director of JPP.

"Knowingly hanging a mentally-ill man would signal to the world that Pakistan does not uphold the fundamental rights of its citizens or abides by its international obligations."

Since lifting its moratorium on executions in December 2014, Pakistan has hanged some 420 prisoners.