The Egyptian authorities, increasingly rattled by pro-reform protests, braced Tuesday for more demonstrations from opposition groups ahead of landmark elections.
After hundreds of supporters of the prohibited Muslim Brotherhood movement demonstrated Sunday in defiance of a government ban, another opposition group called for a march in front of parliament Wednesday.
"Besides asking for a parliamentary republic, we will also march in support of civil liberties and freedom of expression," said the leader of Kefaya (enough) - a coalition group of leftists, liberals and Islamists.
Noting the "growing nervousness of authorities in the face of mounting political dissent," George Isaac said he was "shocked by police repression on Sunday," during the Brotherhood's rally.
Police deployed en masse Sunday to prevent the Brotherhood's supporters from reaching parliament where the demonstration was originally set to take place.
Positioned in compact squares, helmeted, shield-carrying and club-wielding forces managed to prevent any advances by the protestors.
A few hundred marchers, asking for constitutional reforms and the lifting of restrictive emergency laws, managed to gather on the central Ramses square, a mile away from parliament, and in two other downtown spots.
Fifty were arrested for having overlooked the government's demonstration ban, authorities said.
Street demonstrations are forbidden in Egypt thanks to emergency laws that have been in place since president Anwar al-Sadat's assassination in 1981.
Another 50 Brotherhood members had already been nabbed by security forces ahead of the demonstration Saturday.
High-ranking members of the organization were among those arrested in five districts in and around Cairo.
Sixteen of those arrested at the weekend were released and 23 placed in preventive detention for a fortnight, Brotherhood second-in-command Mohammed Habib said Monday.
Judicial sources named the charges as "membership of a banned organization, participation in illegal demonstrations and incitement to hatred of the regime."
The Brotherhood was officially banned in 1954 over its violent anti-government activities. It has a dozen MPs sitting in parliament as "independents."
According to some commentators, the group could however win as many as 20 percent of parliament's 454 seats in a fair election.
Isaac said the Brotherhood would be "symbolically represented" at Wednesday's demonstration.
"We won't demonstrate for amendments to the current constitution but for the establishment of a parliamentary system to replace today's presidential regime," Isaac also said.
Egypt's once had a parliamentary regime under King Farouk, who was overthrown in 1952.
Kefaya will also ask for the appointment of "a constitutional assembly to draft a new constitution" and for "a transitional period" before organizing presidential polls under the new constitution," Isaac also said.
Egyptian President Hosni Mubarak, who has been in office for the past 24 years, asked lawmakers last month to amend the constitution to allow for the first multi-candidate presidential elections in Egypt's history.
But many in the opposition charge that the amendments still greatly curb the possibility of parties fielding candidates as they must first be approved by parliament which is dominated by MPs representing Mubarak's National Democratic Party (NDP).
Brotherhood's Habib also said Monday that his group would support Mubarak's candidacy or that of his son, should either one run for the September 2005 polls "if measures are taken to ensure a smooth presidential election and the state of emergency is lifted."
Gamal Mubarak, 42, recently announced he would not be a candidate while his father has so far remained silent on the subject.
Kefaya, by contrast, squarely rejects "hereditary power" and wants to see an end to Mubarak's "despotic" regime.