By Suleiman Al-Khalidi

AMMAN (Reuters) - Jordan executed 15 people on Saturday, including 10 convicted on terrorism charges ranging from an attack a decade ago on Western tourists to the slaying of a writer in the largest mass execution in the country's recent history.

Government spokesman Mohammad al Momani told state media those executed included one man who was convicted of an attack last year on an intelligence compound near a Palestinian camp that killed five security personnel.

Another five were involved in an assault by security forces on a militant hideout by suspected Islamic State militants in Irbid city in the same year that led to the death of seven militants and one police officer. The rest related to separate incidents that go back as far as 2003.

It was the largest number of executions in one day in Jordan's recent history, said a senior judicial source who was not authorized to speak publicly about the matter and requested anonymity.

At least one hundred detainees have been sentenced to death in recent years, many on charges related to membership of militant Islamist groups, who could face capital punishment.

Sarah Leah Whitson, Middle East director at Human Rights Watch, said in a statement the death penalty was not a deterrence, citing a spike in militant attacks since last year.

"Whatever image of strength Jordan wishes to project, the death penalty will never deter terror attacks and murder, or make the citizens of Jordan safer," Whitson said.

"Just the terror attacks of the last two years shows that reinstating the death penalty in Jordan has done nothing to reduce the incidents of such violent attacks."

Several security incidents over the past year have jolted the Arab kingdom, which has been relatively unscathed by the uprisings, civil wars and Islamist militancy that have swept the Middle East since 2011.

However, Jordan is among the few Arab states that have taken part in a U.S.-led air campaign against Islamic State militants holding territory in Syria and Iraq

Human rights group Amnesty International condemned the executions by hanging, saying they had been carried out in "secrecy and without transparency."

"The scale of today's mass executions is shocking and it's a big step backwards on human rights protection in Jordan," Samah Hadid, deputy director of Amnesty International's Beirut regional office, told Reuters.

Hadid said the death penalty was "problematic because in some cases confessions in Jordan were extracted under torture or duress", echoing widespread complaints by human rights activists.

Amnesty said in a statement earlier: "Jordan had for years been a leading example in a region where recourse to the death penalty is all too frequent."

Jordan in the past refrained from executing political detainees and either reduced or suspended death sentences handed to fundamentalist Islamists on terror-related charges.

International human rights activists say militants are put on trial in military courts that are unconstitutional and lack proper legal safeguards, adding that there are growing cases of mistreatment and of extracting confessions under duress.

The government denies it tortures prisoners or mistreats detainees, saying its courts abide by human rights laws.

Another judicial source said the authorities also executed a man who last year shot dead outside a court a Christian writer who was standing trial for contempt of religion after sharing on social media a caricature insulting Islam.

Also among the 10 was a gunman convicted of firing at a group of Western tourists near the Roman amphitheatre in downtown Amman in 2006, killing one Briton and injuring five other people, the source said on condition of anonymity.

The five other executions were for rape and sexual assault.

Jordan restored the death sentence by hanging in 2014 after a moratorium on capital punishment between 2006 and 2014.

(Reporting by Suleiman Al-Khalidi; Editing by Ed Osmond and Richard Chang)