CAIRO — Several thousand people heeded calls by the Muslim Brotherhood and protested Friday throughout Cairo and other cities against a coup and deadly crackdown as the police and army blocked key roads and beefed up security.

In one of the larger marches of about 5,000 people, protesters chanted slogans against the country's army chief, Gen. Abdel-Fatah el-Sissi, who led the popularly backed July 3 ouster of President Mohammed Morsi, a longtime leader of the Brotherhood.

"The people want the death of the assassin!" the protesters yelled while holding up yellow posters with the outline of four fingers.

Morsi supporters have used the symbol in online and street campaigns to remember the sit-in protest around the Rabaa el-Adawiyah mosque, which in Arabic means fourth.

Security forces cleared out that sit-in and another one two weeks ago in violent raids that sparked several days of violence. More than 1,000 people, most of them people opposed to Morsi's ouster, have been killed since. The Interior Ministry says more than 100 policemen and soldiers have also died in the violence.

Hundreds of Brotherhood members, including top leaders, have been arrested and accused of inciting violence. The fierce security crackdown has weakened the Brotherhood, once Egypt's most powerful political group.

The streets of Cairo were largely empty Friday in anticipation of the protests. Security forces blocked main roads with barbed wire, tanks and armored vehicles to bar protesters from reaching Sphinx Square in Cairo where the Brotherhood called on its protesters to converge and set up another sit-in.

About 150 people protested peacefully outside a mosque near the square after midday Islamic prayers. Security forces fired two canisters of tear gas at the crowd.

Security forces also fired tear gas at about 3,000 protesters in the Nile Delta city of Tanta.

Despite mass arrests, the Brotherhood has been able to get out its message and organize marches through Facebook campaigns. Still, Friday's protests appeared much smaller than those in previous weeks.

"Say it without fear: El-Sissi must go" and "The coup is terrorism" were among pro-Brotherhood chants Friday.

Not all of the protesters were Brotherhood members. Some said they were only seeking justice for relatives killed by security forces this month.

Sherif Osama, a 27 year-old protester, said his cousin was killed during a raid against the Rabaa sit-in and that he is out "to take revenge."

"He was killed by a bullet in his back that went out from the front," he said of his cousin. "At the morgue they wrote on the death certificate that he committed suicide."

Like others, Osama warned that officials from the authoritarian regime of ousted President Hosni Mubarak were behind Morsi's demise and were looking to return to power.

Meanwhile, Egypt's state news agency said unidentified gunmen in two cars opened fire on a police station in the upscale Cairo neighborhood of Heliopolis, killing an officer and a civilian. The drive-by attack early Friday wounded another officer, according to the MENA agency.

The Interior Ministry, which is in charge of police, said in a nationally televised statement Thursday that its forces would deal with "firmness" against acts that threaten national security and that police had orders to use deadly force in defense of public and private property.

The ministry said that the Brotherhood's calls are aimed at stirring chaos. A nighttime curfew in Cairo and 13 other provinces will start earlier on Friday at 7 p.m. and end 6 a.m.