Supporters of Egypt's ousted president Mohammed Morsi hold posters showing victims of a military crackdown on their protest camp during a march in old Cairo on Friday, Aug. 23. (Amr Nabil/AP)

Egyptian authorities closed major mosques, blocked key squares with barbed wire and used a heavy security presence to stymie protests Friday as the military government tightened its hold on the country following deadly clashes last week.

The besieged Muslim Brotherhood had called for mass demonstrations on what it dubbed a “Friday of Martyrs” to show support for ousted president Mohamed Morsi and condemn the government’s violent crackdown on the group last week.

But the turnout in Cairo was light, and only minor clashes were reported in other Egyptian cities.

Whether the response reflected fear or the Brotherhood’s waning authority after the jailing of many of its leaders, it was a stark contrast with the violence that gripped Egypt after Friday prayers a week ago, when gunfire emptied the streets and more than 200 people were killed nationwide, at least 95 of them in the capital alone. Hundreds more were killed earlier in the week after security forces stormed pro-Morsi protest encampments in Cairo, touching off several days of clashes and worry about a possible civil war.

On Friday, however, security forces seemed a step ahead. Soldiers barricaded major institutions and blocked key intersections to prevent demonstrators from reaching Ramses Square downtown, the scene of most of the bloodshed a week ago. Other major gathering spots were closed to traffic. Barbed wire traversed the roads leading to Mustafa Mahmoud Square, for example, and a popular mosque of the same name was watched by army and police patrols.

The large and influential al-Fateh and Rabaa al-Adawiya mosques were shuttered altogether for what the government described on Thursday as “renovations.” The pro-government vigilantes known as Popular Committees, whose presence had contributed to a sense that the capital was sliding out of control, were also nowhere to be seen. The Interior Ministry banned the committees earlier this week.

If the violence has waned, Egypt’s political direction is no more certain, with remnants of two former regimes now in jail or on trial. Morsi, who was ousted by the military in the July 3 coup, is being held at an undisclosed location. Toppled longtime leader Hosni Mubarak has been transferred to a military hospital following his release from prison while his case is on appeal.

The trial of top Muslim Brotherhood officials is scheduled to begin Sunday, another potentially tense moment.

President Obama, in an interview Friday on CNN, hinted at changes in U.S. ties with Egypt, a long-standing strategic relationship bolstered by billions of dollars in U.S. military aid and high-level security cooperation. Obama also said, however, that he is not sure suspending military aid would make much difference in the military-backed government’s decisions.

“There is no doubt we can’t return to business as usual, given what’s happened,” Obama said. “The aid itself may not reverse what the interim government does. . . . But I think what most Americans would say is that we have to be very careful about being seen as aiding and abetting actions that we think run contrary to our values and our ideals.”

While the nation was much calmer than a week ago, there were reports of scattered clashes around the country Friday, pitting pro-Morsi protesters against police and the ample number of Egyptians who backed Morsi’s removal and supported the crackdown.

The most violent appeared to be in the northern city of Tanta, where hospital officials reported 25 injuries and protest organizers said one person was killed. In the Nile Delta city of Mansoura, residents set fire to a Muslim Brotherhood office, according to the Web site of the Sharouk newspaper. The state-run al-Ahram news site reported that hundreds of residents in the city attacked one of the pro-Morsi marches.

The casualty reports could not be independently verified.

In Cairo, only groups of a few hundred at a time were able to muster, and they largely gathered away from the central areas such as Tahrir Square that have served as popular protest venues since the 2011 Arab Spring movement that led to Mubarak’s departure.

On the usually festive Friday afternoon, the heart of the weekend in this Arab capital, stores were closed and streets were empty. Bags of broken glass sat by curbs, swept up after last week’s violence and piled near the wreckage of destroyed vehicles.

In the neighborhood of Giza, on the western side of the Nile near the Pyramids, about 1,000 protesters gathered under a bridge. They carried pictures of Morsi and chanted slogans as other citizens waited for buses a few yards away.

“Islam! Islam!” the demonstrators shouted. “The people want the toppling of the regime!”

In Maadi, a sprawling district in southern Cairo, more than 1,000 protesters wound through narrow, dusty streets, waving posters of Morsi. “There is a revolution in the streets of Egypt!” the marchers chanted. Many held up signs showing a hand flashing four fingers — a symbol of outrage at the storming of a pro-Morsi encampment at Rabaa al-Adawiya on Aug. 14.

More than 500 people were killed that day in raids by security forces on two major protest sites. “Martyrs, martyrs, rest in peace! Wait for us at the gates of heaven!” shouted the demonstrators in Maadi. A few onlookers trained hoses on the crowd to cool the protesters from the scorching midday sun.

In the upper-class neighborhood of Mohandiseen, several hundred people ambled down Mohy el-Din Abul Ezz Street, waving Egyptian flags, demonstrating against the military coup. Some said they had hoped to protest at Mustafa Mahmoud mosque but had left because of the heavy security presence, then simply walked through the neighborhood instead, taking advantage of the unusual lack of traffic.

“We are not all ikhwan,” said Abdel Hamid, a 31-year-old pharmacist, speaking in English but using the Arabic word for brothers to refer to the Muslim Brotherhood. “I am an Egyptian citizen who wants democracy for my country to move peacefully.”

While the heavy security evidently discouraged major protests, one normally well-informed Brotherhood member, who spoke on condition of anonymity for fear of reprisals, acknowledged Friday that the group’s vaunted organizational capacity has been damaged by events of the last few weeks.

“Communication is not what it used to be,” he said.

Philip Rucker in New Milford, Pa., and Liz Sly, Sharaf al-Hourani and Lara El Gibaly in Cairo contributed to this report.