CAIRO -- Egyptian authorities refused entry to two senior Human Rights Watch staffers a day before the organization is due to release a damning report on the mass killing of protesters in Egypt one year ago.
Upon arrival at Cairo International Airport, Executive Director Kenneth Roth and Middle East Director Sarah Leah Whitson were denied entry into the country by airport security.
"They were interrogated, then held through the night and... told they were being deported without any explanation," said Human Rights Watch Fellow Omar Shakir. "All we know is that there was a note affixed to the passports of Ken and Sarah Leah that said 'security reasons'."
Human Rights Watch says this is the first time its staff members have been prevented from entering Egypt, even under three decades of former dictator Hosni Mubarak's rule.
It comes a day ahead of the release of Human Rights Watch's report on last year's mass killings of demonstrators protesting the Egyptian military's overthrow of former President Mohammed Morsi. Roth and Whitson had traveled to Cairo for its scheduled publication on Tuesday.
The report, compiled over the last year and titled "All According to Plan: The Raba'a Massacre and Mass Killings of Protesters in Egypt", concludes that Egyptian security forces "methodically opened fire with live ammunition on crowds of demonstrators... killing at least 1,150 people."
For the organization, today's deportation is an unmistakable signal that President Abdel Fattah al-Sisi and his regime will not tolerate criticism of its violent crackdown on the Muslim Brotherhood.
"In light of what took place it was a very clear signal to us that the government was intending to shut down our release of this report and trying to silence us from presenting our findings," Shakir told CBS News.
The group says that over the past three months it has reached out multiple times to the Egyptian government for comment and to share its findings but has received no response. Last week Human Rights Watch submitted advance copies of the report to Egyptian ministries, embassies and officials.
In a statement issued by Human Rights Watch, Kenneth Roth said, "Instead of denying the messenger entry to Egypt, the Egyptian authorities should seriously consider our conclusions and recommendations and respond with constructive action."
The Egyptian Interior Ministry had no immediate comment on today's deportation. Al-Ahram, an Egyptian state-run newspaper, reported that Roth and Whitson were deported for "refusing to meet the entry requirements of the country", citing security sources.
An Egyptian senior government official told CBS News that authorities would respond to the substance of the Human Rights Watch report following its release tomorrow.
But over the last year the government has consistently shrugged off withering criticism from the international community and human rights groups about its security crackdown, claiming it is fighting a "war on terror".
Shakir, who was the principal researcher of the report, also left Cairo this morning following the deportation of his colleagues. Speaking over the phone from Beirut, he told CBS News that the organization had already sharply curtailed its operations in Egypt.
"In light of the shrinking space for civil society and the detention and arrests of people who were doing nothing more than expressing their rights to free assembly and association - including journalists and human rights defenders - we took the decision in February to shut down our office," he said.
"We will continue to cover Egypt from the outside until conditions allow organizations like ours the space to freely operate," said Shakir.