CAIRO, Feb. 1 -- Egyptian authorities have cracked down on opposition groups in recent days during a time of increasingly active efforts to stop President Hosni Mubarak from extending his 24-year rule in a referendum later this year.
On Saturday, police arrested Ayman Nour, leader of the opposition Tomorrow Party. Prosecutors charged him with falsifying petitions that resulted in the legalization of his party in October. On Monday morning, a court extended the initial four-day detention to 45 days, according to his wife, Gamila Ismail.
"It's a message to him and every party that opposes the government," Ismail said. "Active parties that are serious about opening offices and genuinely recruiting followers will not be allowed."
Ismail said police raided Nour's office and home. They confiscated computers from his house and rifled through medicine cabinets and Nour's tobacco supply, Ismail said, adding, "It was certain they are looking for anything to frame him."
On Friday, police arrested three activists at the Cairo book fair, an annual trade show, as they were handing out leaflets inviting the public to an anti-Mubarak rally scheduled for this Friday.
The arrests followed several months of relative tolerance by the police. Opposition organizations have staged periodic demonstrations to oppose a fifth term in office for Mubarak as well as to voice suspicions that he plans to hand power to his son, Gamal.
"The arrests are an escalation," said Wael Khalil, a member of the Movement for Change, a coalition of anti-Mubarak groups. "There was interim improvement, but it looks like the old intimidation is back."
Police also confiscated books at the fair that demanded an end to Mubarak's rule and arrested 10 students at Minufiya University northwest of Cairo on Sunday.
Government spokesman Ahmed Eissa declined to comment on the arrests. "Wait and see," he advised.
Mubarak's opponents have organized numerous and sometimes quixotic efforts to head off another six-year term of office for the president. Three activists have announced they would run, though many observers say there is little chance that the government will institute multi-candidate elections.
Under current rules, parliament nominates a single candidate, who is then offered for ratification in a referendum. Mubarak's National Democratic Party controls more than 80 percent of the assembly seats. Changing the rules would require a constitutional amendment.
Muhammed Farid Hassanin, a former member of parliament and a declared candidate, campaigned last week at an athletic club near Cairo. He told 200 men in the audience that it was Egypt's "shame" to have another pharaoh.
The speech set off earnest debate, with some audience members chanting in favor of Mubarak. In Hassanin's view, it was a success nonetheless. "People say there is no alternative to Mubarak. For the first time, they have the chance to see one, even if it is just me," he said in an interview later. "Yes, it's strange. A campaign without elections. But we must try everything."
His campaign and the campaigns of the two other challengers -- sociologist Saad Eddin Ibrahim and feminist writer Nawal Saadawi -- come in the context both of domestic ferment in Egypt and a perception that the U.S. government, long an ally of Mubarak, wants change.