By Alexander Dziadosz

CAIRO (Reuters) - Rival protesters in Egypt's capital insist they want to avoid bloodshed during mass rallies against President Mohamed Mursi on Sunday, but both are clearly ready for a confrontation.

As the opposing sides vie for the revolution's mantle, Mursi's Islamist supporters have set up checkpoints around a Cairo rally, recalling the human chains that protected protesters during the 2011 uprising that toppled Hosni Mubarak.

Thickset men stand in rows by guard rails, hefting wooden or plastic rods and wearing hard hats and body armor. They check ID cards and frisk visitors.

"We will defend the revolution, we will defend legitimacy," a banner with a picture of Mursi reads above a stage set up at the rally of a few thousand outside a mosque.

Sunday marks Mursi's first year in office - a period his opponents say is long enough, blaming him and his Muslim Brotherhood for Egypt's economic malaise and accusing them of trying to impose strict religious values on a diverse country.

They now hope mass demonstrations will topple him just as they swept out Mubarak over two years ago.

In Tahrir Square, the epicenter of the 2011 revolt, Abdelhamid Nada, a 32-year-old accountant, pitched a tent late on Friday with eight friends who came from the Nile Delta city of Monufia. He said dozens more would join them and march to the presidential palace on Sunday.

The protests would only get violent if Brotherhood supporters provoked it, he said. "If they are foolish enough, they will do it, and if they do it, we will win."

Nearby, Amr Riad, 26, collected signatures for the "Tamarod - Rebel!" petition drive against Mursi that claims to have collected 22 million signatures. "We're peaceful. But if those who come at us are violent we'll defend ourselves," he said.

Mursi's supporters talk in similar terms. Abdelhakim Abdelfattah, 47, said he came from Suez to join the Islamist protest. Some expected Sunday to pass peacefully, but others feared a repeat of clashes between the two camps that broke out late last year, he said.

If Mursi's supporters sensed the president was under threat, they would go to the streets in even greater numbers, he added.

"They'll come down to defend his legitimacy, not with weapons, but with their bodies," Abdelfattah said. "What's the nature of this legitimacy? The ballot box."

U.S. President Barack Obama called on Egypt's government and opposition on Saturday to engage each other in constructive dialogue and prevent violence spilling out across the region.


Islamists and liberals, Christians and Muslims alike, joined together in Tahrir during the revolt against Mubarak, holding the square against attackers who hurled rocks and petrol bombs and, at one point, charged the crowd on horses and camels.

They have diverged sharply since then, and both sides now claim to be the true representatives of the revolution, in some cases even using the same chants.

Mursi's detractors say Islamists have hijacked a revolt that started as an inclusive call for democracy. Supporters say the president's opponents are riddled with Mubarak loyalists who want to undermine Egypt's first elected leader.

"This isn't an opposition," Islamist protester Mohamed Amer, 59, said of anti-Mursi demonstrators. "These are gangs taking money from who-knows-what-source to destroy the country. If there was a proper opposition we'd return to the ballot box."

Violence has already spread throughout the Delta and cities along the Suez Canal. The Muslim Brotherhood says eight of its offices were attacked on Friday and five of its supporters have been killed this week.

Two people, including a 21-year-old American student, died in the port city of Alexandria when protesters stormed a Brotherhood office. A third man was killed and 10 injured in a blast at a protest in Port Said.

Many of Mursi's opponents now call openly for Egypt's army to intervene, as it did when it pushed out Mubarak in 2011 and imposed temporary military rule. The military says it would step in if the situation on Sunday got out of hand.

At the Islamist rally on Saturday, one man said the Brotherhood had banned supporters from wielding knives and firearms to avoid such an escalation.

"We only have sticks," he said. "We can bear it without reacting if they kill one, or two, or ten of us. We'll bear it to avoid entering a cycle of violence none of us escape."

(Reporting by Alexander Dziadosz; Editing by Alastair Macdonald/Mark Heinrich)

[Image: Protesters opposing Egyptian President Mohamed Mursi wave Egyptian flags and a placard reading "Leave", during a protest against him and members of the Muslim Brotherhood at Tahrir square in Cairo June 29, 2013. By Amr Abdallah Dalsh for Reuters]