CAIRO — Thousands supporting Egypt's ousted president marched in street protests Friday across the country, ramping up pressure on the military-backed interim government ahead of his coming trial next week.

Supporters of toppled President Mohammed Morsi in Cairo and other major cities denounced the trial, which starts Monday, as "void." They instead called it a trial "of the people's will."

"Stay strong, Mr. President, we are behind you with a million martyrs," protesters chanted in video footage aired on the satellite news network Al-Jazeera. Military chief Gen. Abdel-Fattah el-Sissi, who led the July 3 coup against Morsi's government, was the target of increasingly hostile chants, including one calling for his "execution in the square."

Abdel-Hamid el-Musalmani, one of the protesters, said the rallies Friday are focused on calling for the trial to be stopped.

"The charges [against Morsi] are all fabricated," he said.

In Egypt's second-largest city, Alexandria, police fired tear gas to break up clashes between Morsi supporters and neighborhood residents who oppose his Muslim Brotherhood group.

The protests Friday were a rehearsal for larger rallies planned for the day of the trial, organizers said. Authorities say some 20,000 police officers and soldiers will guard the area where Morsi's trial will begin Monday and other locations out of fears that Morsi supporters could disrupt the court hearing or start clashes.

Morsi faces charges of inciting his supporters to murder his opponents during deadly clashes in front of the presidential palace in December. He has not been seen publicly since the coup and has been held by the military in an undisclosed location.

Morsi's trial is expected to take place inside a police institute near a prison complex in southern Cairo.

Islam Tawfiq, a member of the Brotherhood's youth group, denied claims that group is planning violence on Monday or will try to liberate Morsi by force.

"Morsi will be liberated only when the popular revolution that has been in the streets for over 100 days succeeds," he said.

Tawfiq did say supporters plan massive rallies on the day of the trial around the venue. A coalition of Morsi supporters led by the Brotherhood has called for massive demonstrations Monday nationwide, and in front of Egypt's embassies and consulates abroad.

"We will make this day an international day of protest," the coalition said in a statement.