Credit: Khaled Kamel/AFP/Getty Images

Tens of thousands of pro-Islamist protesters poured into eastern Cairo Friday night to rally in support of ousted president Mohammed Morsi.

Answering the Muslim Brotherhood's call for a "million-man march" on the first Friday of the holy month of Ramadan, protesters held signs reading "Down With the Military Rule" and "No to Treason, No to Military Coup." The main sit-in outside Rabaa al Adawiya Mosque in the Cairo suburb of Nasr City remained peaceful during the day, featuring singers and Islamic readings, patriotic music and a banner reading "Anti-Coup" in English.

"We are ready to stay for a month, two months, a year, or even two years," ultraconservative Salafi cleric Safwat Hegazi told protesters, according to The Associated Press. Tents have been erected and makeshift walls constructed suggesting Morsi's supporters may be gearing up for the long haul.

Expecting big numbers Friday night, the military announced security would be beefed up in central areas of the capital to avoid clashes.

The Wall Street Journal's Matt Bradley reported from Rabaa al Adawiya Friday night:

Huge crowds are now flowing into Raba'a al Adiwiya Square. #egypt

- Matt Bradley (@MattMcBradley) July 12, 2013

Just left Raba'a Al Adiwiya. A lot of anger there. #egypt

- Matt Bradley (@MattMcBradley) July 12, 2013

Muslim Brotherhood spokesman, Gehad El-Haddad announced a march was leaving Rabaa al Adawiya mosque at 10:30pm Friday night.

A march will leave #Rabaa 10:30p towards Ministry of Defense, will announce demands of #AntiCoup mvmnt b4 returning back 2 Rabaa. #Egypt

- Gehad El-Haddad (@gelhaddad) July 12, 2013

The New York Times' Ben Hubbard is at central Cairo's Ramses Square:

Ramses square. Huge pro Morsi march headed to Sit in in Nasr City. pic.twitter.com/QOmp5Q3YFE

- Ben Hubbard??? ????? (@NYTBen) July 12, 2013

While the Daily Beast's Mike Giglio reports that after filling Ramses Square around midnight in Cairo, the protesters are headed back to Rabaa al Adawiya.

Pro-Morsi protesters in Ramses now saying they've been called back to Rabaa. Warning shot?

- Mike Giglio (@mike_giglio) July 12, 2013

And just like that, they reopened Ramses and are heading back to Rabaa. Chanting, "Morsi is my president!" as they go.

- Mike Giglio (@mike_giglio) July 12, 2013

In Tahrir Square, Tamarod, "Rebellion" in Arabic, the youth-led group behind last week's protests that led to the overthrow of Morsi, planned communal iftar meals to celebrate breaking fast during Ramadan. At this time, Morsi's supporters have not approached Tahrir Square and no violence has been reported.

In Washington, the State Department dialed up its rhetoric Friday, calling on Egypt's military and interim government to release Morsi. State Department spokeswoman Jen Psaki said the U.S. agrees with the German Foreign Ministry, which urged an "end to all restrictive measures considering Morsi." Ten days after his ouster, the U.S. believes Morsi remains at the Republican Guard Headquarters.