By Ahmed Aboulenein

CAIRO, Jan 20 (Reuters) - Egyptian activists Ali al-Khouly and Mohamed Ali had just sat down at a Cairo coffeeshop when plainclothes officers grabbed them and hauled them off to a police station. What they most wanted to know was: what are your plans next Monday?

As the fifth anniversary of Jan. 25 protests that ended Hosni Mubarak's 30-year rule approaches, the toughest security crackdown in Egypt's history is a clear sign that authorities are worried.

"They are employing scare tactics because they themselves are frightened," Khouly told Reuters a day after his release. "I honestly have no idea why I was taken or why I was released but there is no justification for this horror."

With thousands of government opponents behind bars, the likelihood of massive protests is slim. However, analysts and activists say, the crackdown reveals an insecurity that has grown since general-turned-president Abdel Fattah al-Sisi ousted the Muslim Brotherhood from power two years ago.

Then, Sisi's popularity was sky-high. But with a promised economic revival having yet to materialise and the threat of Islamist militancy looming, he is at pains to stamp out open dissent, they say.

"There is a high level of paranoia on the part of the government. It is an inadvertent admission that there have been a number of failures," said Timothy Kaldas, nonresident fellow with the Tahrir Institute for Middle East Politics.

After the military ousted the Brotherhood's President Mohamed Mursi following protests against his rule, the group was able to mobilise thousands onto the streets. But security forces have since killed hundreds of his supporters and jailed thousands, accusing the group of terrorism.

Authorities have since expanded their sweep. Over the past few weeks, they have rounded up scores of activists, closed down cultural centres and worked to ensure imams tell their followers that protests against Sisi are sinful.

In recent days, police have also been conducting mass searches of flats, primarily in the downtown Cairo area near Tahrir Square, epicentre of the 2011 uprising. They say they have found dozens of foreigners who have overstayed their visas, recalling the Mubarak government's actions in 2011, when foreigners were accused of inciting protest.

Khouly and Ali, both secular, are not prominent activists but they were still caught up in the dragnet and held for five hours at a police station, their lawyer said.

They were separated and questioned about their political views and opinion of Sisi, and whether or not they would protest on Jan. 25.

Opprssion the fuel of protest

While Sisi remains popular among many Egyptians, he no longer enjoys the reverence which once saw his image, complete with a military beret and sunglasses, on everything from posters to women's underwear in this conservative Muslim nation.

One negative is the economy, which remains in the doldrums with a rising cost of living and stagnating wages, Kaldas said.

Egypt also faces an Islamic State insurgency in the Sinai, a strategic peninsula bordering Gaza, Israel and the Suez Canal, where militants have killed hundreds of soldiers and police. Sisi has promised to end the militancy but results are mixed.

"This is a regime that knows it has something to be scared of. It knows it did not achieve what Egyptians expected," said Ayman al-Sayyad, the editor of Weghet Nazar political journal.

But most Egyptians are not actively in opposition to Sisi, Ali said, and many activists are tired of confronting what human rights groups say is an increasingly ruthless state in the face of such apathy.

"It's just not happening, we can't force people. Even if we oppose the regime we must respect the public's wishes," Khouly said.

Reuters spoke with three other activists who declined to be named for fear of reprisal, in contrast to the days when Egyptians took to Tahrir Square by the hundreds of thousands.

They all said they would stay home on Jan. 25 after many colleagues were arrested and their gathering places shut down.

Many of those arrested are not prominent activists but run Facebook pages calling for demonstrations. Marches and rallies in 2011 were often organised by youth activists on Facebook and other social media platforms.

At least four cultural spaces, including an art gallery and a publishing house in downtown Cairo, were either raided or shut down in the past month.

"We have taken several measures to ensure activists don't have breathing space and are unable to gather, and several cafes and other meeting places have been closed, while some have been arrested in order to scare the rest," an official at the Homeland Security Agency told Reuters.

Two employees of the Town House art gallery described how 20 people, many of them police officers, raided the premises under the guise of administrative violations. It remains shut down.

"Security forces believe in beating the citizen until they reach an agreement; they believe in fear and intimidation," said Mohamed Hashem, owner of Merit publishing house, which was raided the day it was scheduled to hold a seminar by an author of a book about corruption.

The Ministry of Religious Endowments, which supplies preachers with weekly talking points and scripture to quote, has also joined the campaign.

The last two Friday prayer sermons explicitly warned against protesting on Jan. 25. One, entitled "The Blessing of Safety and Security", says that those who aim to disrupt stability are committing a major crime in the eyes of God.

Political analysts said the government is walking a fine line between discouraging protest and squeezing too hard.

"Oppression is the fuel of protest and protest is the first step to violence," Sayyad said.

"The regime fears reaping what it has sown." 

(Additional reporting by Ahmed Mohamed Hassan and Mostafa Hashem)