A court in Saudi Arabia has sentenced a Palestinian poet to death for renouncing his religious faith, according to documents seen by Human Rights Watch.

Ashraf Fayadh was handed the sentence on Tuesday on charges of “doubting the existence of God,” according to court documents seen by the group’s Saudi Arabia researcher, Adam Coogle.

Fayadh, who was born to Palestinian parents but grew up in the Gulf kingdom, was arrested by religious police in late 2013 after a reader complained that one of his books, his 2008 poetry collection Inner Teachings, could encourage people to renounce Islam.

Fayadh, now 50, was released after a day due to lack of evidence, but was rearrested in January 2014 in the southwestern city of Abha.

The poet was arrested in a coffee shop after watching a game of football, and was threatened with being deported to Gaza, his father told France24 at the time.

Fayadh was initially sentenced to four years in prison and 800 lashes, but an appeal judge this week increased the sentence, handing down the death penalty.

The exact charges under which Fayadh was initially held were not made clear, although some have suggested that his arrest was linked to his publication of a video showing religious police in Abha beating a young man in public.

The arrest of Fayadh, also an expressionist artist who has shown his work in government-sponsored exhibitions, sparked anger last year, with hundreds of artists and writers signing a petition calling for his release.

Following news of the death sentence against Fayadh, the Arabic Network for Human Rights Information put out an urgent call for charges against him to be dropped.

Saudi Arabia has put to death nearly 150 people so far this year, the highest figure in two decades.

Most people are executed by beheading with a sword, a method Saudi authorities say is more humane than other alternatives.

Public executions remain common – filming such events is illegal, but activists recently circulated rare footage that captured a triple beheading.

The vast majority of death penalties handed down in the kingdom are for either non-violent drugs offences or murder, although there are exceptions.

The case of Ali al-Nimr, sentenced to death aged 17 after taking part in peaceful protests, has sparked an international outcry, with David Cameron, the British prime minister, stepping in to urge Saudi authorities not to carry out the execution.