CAIRO — Egyptian security forces targeted one of the last remaining independent news outlets in the country on Saturday, taking a journalist from his home and detaining him in an unknown location, according to the news site.

Four plainclothes security officers knocked on the door of Shady Zalat, an editor with the Mada Masr news website, before dawn and entered without presenting an arrest warrant, it reported.

They confiscated the laptops of Zalat and his wife, as well as work documents and his cellphone, before taking Zalat away.

“He has done nothing more than use words to report the news,” Mada Masr said in a statement posted on its Facebook page.

 Zalat’s arrest is the latest sign of a widening crackdown on freedoms by the government of President Abdel Fatah al-Sissi, a key American ally running what critics describe as the most authoritarian regime in Egypt’s modern history.

Since Sept. 20, when a small but rare street protest broke out challenging the Sissi regime, the government has arrested more than 4,400 people, including activists, journalists, even children and some foreigners, according to local human rights activists.

“We believe that it is a message from the authorities that our time has come as well,” said Lina Attalah, the editor in chief of Mada Masr.

Egypt is among the world’s top jailers of journalists, according to Reporters Without Borders, the Paris-based press watchdog group. Some detainees have spent years in custody without being charged or facing a trial.

Under Sissi, censorship has significantly grown, with more than 500 websites, including Mada Masr, blocked. Media outlets have been shut down, while others have been taken control by the government or Sissi’s allies.

Egyptian authorities could not be reached for comment, but they have publicly said that many of those arrested since Sept. 20 were “deluded” by fake social media posts and forces plotting against Egypt.

Human rights groups and activists took to social media denouncing Zalat’s arrest. Many viewed it as a warning shot against the few independent voices still courageously willing to hold the government accountable.

“Awful news: #Egypt security thugs arrest @Madamasr editor #ShadyZalat from his home as government apparently commences attack on country’s last remaining independent publication,” tweeted Sarah Leah Whitson, Human Rights Watch executive director for the Middle East and North Africa.

 Mada Masr — roughly translated in Arabic as “scope” or “range” of Egypt — is widely considered the nation’s most authoritative media outlet.

Published in English and Arabic, the publication is known for its investigations and critical reporting. It has probed sensitive topics including the ongoing repression, corruption and the inner workings of the secretive security and intelligence services.

 Despite its website being blocked, Mada Masr has continued to publish on Facebook and other social media.

Recently, the publication published a widely read story about the apparent sidelining of Mahmoud al-Sissi, one of the president’s sons, from a powerful post in the country’s intelligence services.

 Even before that article was published, Zalat was under surveillance, Attalah said.

 Earlier this month, security agents came to Zalat’s apartment building three times in a single night to question the doorman about Zalat’s home, car and work. The 37-year-old editor, who lives with his wife and daughter, has worked at Mada Masr since 2014.

 He is the second journalist at the paper to be detained. In 2015, Hossam Baghat, a well-known investigative journalist was briefly held by the Sissi government for “publishing false news that harms national security.”

The security agents told Zalat’s wife that he was being taken to the security headquarters in Cairo’s Giza enclave. But as of Saturday evening, Attalah said, his whereabouts remained unknown. At least two activists arrested after Sept. 20 have allegedly been tortured by security agents, say human rights activists.

“The authorities must release him immediately and unconditionally,” the watchdog group Amnesty International wrote in a tweet. “They must ensure that he is protected from torture, allow him access to a lawyer and contact with his family,”

The journalists at Mada Masr are bracing for more attacks by the government.

“What happened to Shady is only the beginning of what could be an imminent crackdown on the entire operations,” said Attalah. “What the authorities have done since September 20 is to break all sorts of red lines. They are testing how much more [they] can get away with to carry on their crackdown.”

“And so long as there is silence, they will be more and more emboldened to crack down on us.”