JERUSALEM — A day after militant Islamist group Hamas updated, and some say softened, its founding charter, an international human rights watchdog slammed the group as “cruel” and “torturous” over its continued incarceration of two Israelis with serious mental health conditions.

In a report published Tuesday, Human Rights Watch shed light on the disappearance of Avera Mangistu, an Israeli Jew of Ethiopian descent, and Hisham al-Sayed, a Bedouin Israeli. Both men were seen on Israeli security cameras entering Gaza, Mangistu in September 2014 and Sayed in April 2015.

Neither has been heard from since.

Hamas has not confirmed that the men are in Gaza, but it has not denied it either. Over the past two years, officials from the Strip have made coy references to them and to the bodies of two Israeli soldiers killed in the 2014 summer war between Israel and Hamas.

Two weeks ago, Hamas leader, Khaled Meshal declared that “any information about Israeli captives would carry a price” — indicating the two men are to be used as bargaining chips in exchange for Hamas combatants serving time in Israeli jails.

Hamas officials interviewed for the Human Rights Watch report suggested the two Israelis were legitimate prisoners of war because every Israeli male serves in the army. In one instance, the group’s military wing, Izz ad-Din al-Qassam Brigades, published computer-altered photographs of the men dressed Israeli army uniforms.

A Human Rights Watch investigation revealed that both Mangistu and al-Sayed were rejected from Israeli military service on the grounds of their mental health.

“Hamas’s refusal to confirm its apparent prolonged detention of men with mental health conditions and no connection to the hostilities is cruel and indefensible,” said Sarah Leah Whitson, Middle East director at Human Rights Watch. “No grievance or objective can justify holding people incommunicado and bartering over their fates.”

The scolding from the Human Rights Watch comes as Hamas tries to rehabilitate its standing in the world. The Islamist militant group is viewed as a terrorist organization by Israel and the United States. But on Monday, it released a new manifesto rebranding itself as an Islamic national liberation movement. While it no longer explicitly calls for the destruction of Israel, it does retain the goal of “liberating” historic Palestine.

The report also came out on the eve of Wednesday's meeting between Palestinian President Mahmoud Abbas and President Trump at the White House. Though Abbas is the elected leader of the Palestinian Authority, which controls the West Bank, he has no sway with Hamas.

Research for the report was carried out in September 2016, the first time since 2008 that Israel had allowed representatives of the nongovernmental organization to enter Gaza, an area that has been under an Israeli and Egyptian land and sea blockade since Hamas took control in 2007.

Israel has not been sympathetic to the work of Human Rights Watch, often claiming that the organization singles Israel out on its human rights violations, while overlooking some of the world’s worst violators. In February, an American investigator from Human Rights Watch was denied entry to Israel on the grounds that the NGO is “systematically anti-Israel” and works as a tool for pro-Palestinian propaganda.

This time, however, it is Hamas that is failing to comply with international humanitarian law by breaking commitments made in April 2014 under the Convention on the Rights of Persons with Disabilities. Under the treaty, states must “provide protections for people with psychosocial, or mental health, disabilities,” wrote Human Rights Watch in its report.

According to the report, Mangistu, 30, entered Gaza through a barbed wire fence near a beach on Sept. 7, 2014. Sayed, 29, simply walked across the border into Gaza on April 20, 2015.

The family of a third Israeli citizen, Jumaa Abu Ghanima, also said their son had disappeared into Gaza, sometime in July 2016. Human Rights Watch, however, wrote it could not independently corroborate that account.

“Mangistu and al-Sayed, an Ethiopian Jew and Palestinian Bedouin with mental health conditions, come from among the most marginalized communities in Israeli society,” Whitson said. “There is nothing patriotic or heroic in forcibly disappearing them.”

The group’s calls on Hamas to unconditionally disclose the men’s whereabouts and release them “unless they can provide a credible legal basis for continuing to hold them.” It also said Hamas should allow the men to immediately make contact with their families.

Israeli has also called on Hamas to return Mangistu and Sayed, as well as the bodies of Hadar Goldin and Oron Shaul, the two Israeli soldiers killed in the 2014 summer war between Israel and Hamas.