Reem Mohamed Desouky, pictured with her son, was jailed for criticizing the Egyptian government.

When Reem Mohamed Desouky arrived from Washington last month with her 13-year-old son, Egyptian authorities detained them at the airport, she said. They confiscated their phones and interrogated Desouky, holding the two for hours.

Then, they jailed Desouky, a Pennsylvania teacher and dual U.S.-Egyptian national.

Her alleged crime was criticizing the Egyptian government on Facebook.

Desouky's arrest is the latest example, human rights activists say, of how the government of President Abdel Fatah al-Sissi, one of the Trump administration's closest allies in the Middle East, is silencing its critics. The regime has been cracking down on various forms of expression, especially online criticism of Sissi's rule and any postings perceived as tarnishing Egypt's image.

Egyptian authorities have charged Desouky with administering social media accounts deemed critical of the regime. But officials have not disclosed what offending posts, if any, led to her arrest. One Facebook page from which Desouky shared posts, according to her supporters, is a forum mostly about social and economic conditions in Egypt.

"Her arrest is emblematic of the levels of repression Egypt has reached under Sissi," said Mohamed Soltan, who leads the Freedom Initiative, a human rights group based in the District of Columbia that focuses on political prisoners in the Middle East.

Soltan, also an Egyptian-American, was a political prisoner himself, imprisoned for nearly two years in Egypt.

The Egyptian government did not respond to requests for comment.

Michael Harker, a spokesman at the U.S. Embassy in Cairo, wrote in an email that "we are aware of Ms. Desouky's case and are providing consular services at this time." He declined to elaborate.

Another U.S. Embassy official added that "as always, when we learn of the report of a detained U.S. citizen, we always request consular access to the Egyptian authorities. For privacy reasons, we have nothing further to share."

Desouky's relatives and her lawyer said that no U.S. consular officer has visited her in jail since she was arrested more than a month ago.

Last week, when her brother, Nour, visited her, he was also jailed. Her son, Moustafa Hamed, is staying with relatives in Cairo, hoping that he and his mother can return home to Lancaster, Pennsylvania, before school begins at month's end.

"I just want my mother back," Moustafa said. "She didn't do anything wrong." His relatives in Cairo gave permission for him to be interviewed by phone.

As many as 18 Americans are currently jailed in Egyptian prisons, "but the State Department says most of those are detained for nonpolitical charges," said Amr Magdi, a Human Rights Watch researcher. The group says that at least three, including Desouky, are being held on politically motivated charges or based on flawed trials with lack of due process, Magdi added.

Khaled Hassan, a limousine driver from New York, was picked up by security agents last year and allegedly tortured and raped in custody, the group said. Egypt denies the allegations and accuses Hassan of joining an Islamic State affiliate in the northern Sinai. Hassan has denied those charges and says he was in Egypt to visit relatives.

Moustafa Kassem, an American businessman from New York, has been detained since 2013 when he was picked up during street protests that followed the military coup that ousted Islamist President Mohamed Morsi, the country's first democratically elected head of state.

He was held without charges for five years, then accused along with 738 other inmates of trying to overthrow the Sissi government. In September, a court sentenced Kassem to 15 years in prison. The late senator John McCain, R-Ariz., asked President Donald Trump to demand that Egypt release Kassem, and Vice President Pence urged Sissi to do so. Egypt has declined.

Other unjustly jailed Americans have been freed after pressure from the White House. In 2017, aid worker Aya Hijazi was released after Trump pressed Sissi. Last year, Ahmed Etiwy was freed after Pence urged his release. Etiwy, like Kassem, had been rounded up during protests after Morsi's ouster.

Sissi, a former general who engineered the coup, has deepened a crackdown of Morsi's Muslim Brotherhood movement, jailing tens of thousands of its members. Basic freedoms have been stifled and the government has engaged in torture, extrajudicial killings, arbitrary arrests and forced disappearances of critics, according to the State Department's human rights report.

Supporters of the president credit him with restoring stability after the political chaos that followed the 2011 Arab Spring revolution that ousted longtime autocratic president Hosni Mubarak.

Critics say Sissi has been emboldened by Trump. The repression has grown ever since Trump signaled in a May 2017 speech in Saudi Arabia that human rights in the Middle East would not be a priority for the White House.

Since then, Sissi's government has blocked or shut down hundreds of websites deemed critical of its policies. Last year, Egypt's parliament passed a law tightening restrictions on reporters and social media, granting the government far-reaching censorship powers. Journalists, bloggers and authors of dissenting social media posts have been arrested.

Last year, a human rights activist and a Lebanese tourist were sentenced to two and eight years in prison, respectively, for posting Facebook videos about their alleged sexual harassment in Egypt. Authorities said they were "spreading false news."

Desouky, an arts teacher who also worked as an Arabic translator, emigrated to the United States 15 years ago. Her son was born in Pennsylvania. They flew to Egypt on July 7 to finalize Desouky's divorce paperwork and to see relatives. It had been four years since their last visit, Moustafa said.

After Egyptian authorities inspected their passports, the pair were told to wait. After half an hour, mother and son were taken to a room, where they were held for three hours.

"We kept asking 'What's wrong?' " Moustafa said.

Ultimately, the security officials demanded both their phones and began to scroll through Desouky's contacts, photos, videos and social media posts, he said. They asked them questions such as why they came to Egypt and about her social media activity.

"They asked my mother if she liked Sissi or Morsi," Moustafa said. "She didn't want to reply. She knew you would go straight to prison."

But the security officials were not satisfied. Desouky was separated from Moustafa, who was picked up by his uncle.

Soltan corroborated key aspects of Moustafa's account.

Desouky was transferred to the country's state security agency headquarters in the Nasr City enclave of Cairo, Soltan said. She was later interrogated again in the state security prosecutor's office about her political leanings and social media activity, he said. She was then added to a 2018 case, joining others accused of using social media to undermine the country.

On July 10, Desouky was transferred to Cairo's Qanatir Prison, the nation's largest women's prison. She suffers from asthma and chronic back pain, Soltan said, and there's concern about whether she will receive adequate medical treatment.

Since her incarceration, Moustafa has seen his mother once - for a 10-minute visit, he said.

Last week, when Moustafa and his uncle Nour went to the prison to visit her and bring her a toothbrush, shampoo and other supplies, only Nour was allowed to enter. He never reemerged.

Nour, who is not an American citizen, faces the same charges as his sister, Soltan said.

"Now, everyone in my family is scared to visit my mom," Moustafa said.