Egyptian authorities have intensified a crackdown on dissent ahead of the anniversary next week of the country's 2011 Arab Spring uprising, with police raiding apartments seeking signs of plans for organized protests and checking people's social media accounts.

Security forces have questioned residents and searched more than 5,000 homes in central Cairo as "precautionary measures" over the past ten days, aiming to ensure Egyptians do not take to the streets as they have so many times in recent years, officials said Thursday. Surveillance and intelligence was gathered over months, focusing on young, pro-democracy activists inside and outside the country, including foreigners, an unnamed senior security official said. He added that some people have also been detained. "We are very concerned and will not allow protests," he said, speaking like his colleague on condition of anonymity, because he was not authorized to brief reporters. "These movements are aimed at polarizing society and mobilizing the masses against the government," he added.

Security forces nationwide are bracing themselves for the anniversary of the 2011 revolt that toppled longtime autocrat Hosni Mubarak. Officials, including Egypt's nominal President Abdel-Fattah el-Sissi, have voiced concern over attempts to mark the anniversary with new protests and security forces have arrested a number of activists accused of planning demonstrations.

With thousands of Muslim Brotherhood members and even secular activists in jail, and many others having fled Egypt since el-Sissi led the army's 2013 coup and overthrow of the elected president Morsi, massive demonstrations are unlikely in the capital's greater area, home to some 20 million inhabitants.

The security presence and incursions in Cairo have been greater than in previous years, when authorities also feared anniversary protests. The roundup of activists and the closure of several cultural venues in Cairo considered by authorities to be possible harbors for dissenting views also marked an escalation from previous pre-emptive clampdowns by security services.

Social media users have been particularly targeted this year, with several people affected by the roundups, saying that police are asking to inspect Facebook and Twitter accounts to track acquaintances and gauge political affiliations.

Earlier this month, authorities arrested three people who administered over 20 Facebook pages, accusing them of using the networking website to incite against state institutions. Social media, particularly Facebook and Twitter, played a large part in organizing the 2011 uprising and other protests since then.

One Facebook event page that had been calling for mass demonstrations at Cairo's central Tahrir Square, the epicenter of the 2011 revolt and subsequent protest movements, was cancelled earlier this month after more than 50,000 users said they would attend, and a similar amount expressed interest in the event.

In central Cairo there has been a heightened police presence in recent days, with riot trucks and civilian cars carrying plainclothes officers prowling the streets day and night, often accompanying forces raiding apartments.

One resident, an online marketer, arrived home earlier this week to find a dozen plainclothes officers inside his building, coaxing the doorman to ask residents to cooperate by offering up their mobile devices for inspection. "They wanted to see my mobile phone and my friend's tablet and they were checking others in the building," he said, speaking on condition of anonymity for fear of repercussions.

The anniversary comes at a time when the Egyptian economy, buttressed in the early days of el-Sissi's leadership by aid from Saudi Arabia and the Gulf, is growing slower than authorities had hoped, casting a cloud over el-Sissi's promises to set the country on track to prosperity. At the same time, a wave of suicide bombings and militant attacks has intensified in the country. Over the past year, most of these attacks were claimed by DAESH, who also claimed responsibility for a bomb attack that killed nine people in Cairo on Friday.

Egypt has been roiled by violence and turmoil since the military coup in 2013 led by the current President Abdel Fattah al-Sissi. The former President Mohamed Morsi, the country's first freely elected civilian president, has been imprisoned since mid-2013, after he served only one year in office. In the more than two years since, security forces have killed hundreds and detained tens of thousands of Brotherhood members and Morsi supporters. Hundreds have been sentenced to death after speedy mass trials described by the United Nations as "unprecedented in recent history."