Internet service in Egypt was disrupted and the government deployed an elite special operations force in Cairo today, hours before an anticipated new wave of anti-government protests.
The developments were a sign that President Hosni Mubarak's regime was toughening its crackdown following the biggest protests in years against his nearly 30-year rule.
The counterterrorism force, rarely seen on the streets, took up positions in strategic locations, including central Tahrir Square, site of the biggest demonstrations this week.
Facebook and Twitter have helped drive this week's protests. But by Thursday evening, those sites were disrupted, along with cell phone text messaging and BlackBerry Messenger services. Then the Internet went down.
Earlier, the grass-roots movement got a double boost -- the return of Nobel peace laureate Mohamed ElBaradei and the backing of the biggest opposition group, the Muslim Brotherhood.
The real test will be whether Egypt's fragmented opposition can come together, with today's rallies expected to be some of the biggest so far.
Social networking sites were abuzz that the gatherings called after prayers today could attract huge numbers of protesters demanding the ouster of Mubarak. Millions gather at mosques across the city on Fridays, giving organizers a vast pool of people to summon.
Mubarak, 82, has not been seen in public or heard from since the protests began Tuesday with tens of thousands marching in Cairo and a string of other cities.
Violence escalated Thursday at protests outside the capital. In the flash point city of Suez, along the strategic Suez Canal, protesters torched a fire station and looted weapons that they then turned on police. The Interior Ministry said in a statement that more than 90 police officers were injured in those clashes. There were no immediate figures on the number of injured protesters.
In the northern Sinai area of Sheik Zuweid, several hundred Bedouins and police exchanged gunfire, killing a 17-year-old. About 300 protesters surrounded a police station from rooftops of nearby buildings and fired two rocket-propelled grenades at it, damaging the walls.
The United States, Mubarak's main Western backer, has been publicly counseling reform and an end to the use of violence against protesters, signs that the Egyptian leader may no longer be enjoying Washington's full backing.
In an interview broadcast live on YouTube, President Obama said the anti-government protests filling the streets show the frustrations of Egypt's citizens. "It is very important that people have mechanisms in order to express their grievances," Obama said.
In a move likely to help swell the numbers on the streets, the Muslim Brotherhood ended days of inaction to throw its support behind the demonstrations.
ElBaradei, the former head of the U.N. nuclear watchdog and a leading Mubarak opponent, has sought to re-create himself as a pro-democracy campaigner in his homeland. He is viewed by some supporters as a figure capable of uniting the country's fractious opposition and providing the movement with a road map for the future.