CAIRO (AP) -- Enraged Islamists pushed back Friday against the toppling of President Mohammed Morsi, as tens of thousands of his supporters took to the streets vowing to win his reinstatement and clashed with their opponents in violence that killed 30 and drove the divided nation toward an increasingly dangerous showdown.
In a battle on a bridge over the Nile River in Cairo, gunfire rang out and flames leaped from a burning car as the rival camps threw volleys of stones and fireworks at each other. Military armored vehicles raced across the bridge in a counterattack on Morsi's supporters.
The clashes accelerated after the supreme leader of Morsi's Muslim Brotherhood defiantly proclaimed that his followers would not give up street action until the return of the country's first freely elected president, swept out of power days earlier by the military. Morsi opponents called out the public to defend against the Brotherhood, deepening the battle lines.
In scenes of mayhem, troops opened fire on peaceful pro-Morsi protesters. Islamists threw one opponent off a rooftop.
"God make Morsi victorious and bring him back to the palace," Brotherhood chief Mohammed Badie proclaimed before cheering supporters at a Cairo mosque in his first appearance since the overthrow. "We are his soldiers we defend him with our lives."
Badie said it was a matter of honor for the military to abide by its pledge of loyalty to the president, in what appeared to be an attempt to pull it away from its leadership.
"Your leader is Morsi. ... Return to the people of Egypt," he said. "Your bullets are not to be fired on your sons and your own people."
Hours later, Badie's deputy, Khairat el-Shater, considered the most powerful figure in the organization, was arrested in a Cairo apartment along with his brother on allegations of inciting violence, Interior Ministry spokesman Hani Abdel-Latif told The Associated Press.
After the speech, a large crowd of Islamists surged across 6th October Bridge over the Nile toward Tahrir Square, where a giant crowd of Morsi's opponents had been massed all day. Battles broke out there and near the neighboring state TV building. Pro-Morsi youth shielded themselves from flying stones and fireworks with sheets of barricaded metal. A car burned at the top of an exit ramp amid the sounds of automatic weapons and shotguns.
"They are firing at us, sons of dogs! Where is the army?" one Morsi opponent shouted as another was brought to medics with his jeans soaked in blood from leg wounds. At least three people were killed at the bridge.
The fighting ended when at least seven armored personnel carriers sped across the bridge, chasing away the Morsi supporters. Young civilians jumped onto the roofs of the APCs, shouting insults at the Islamists and chanting, "The people and army are one hand."
Across the country, clashes erupted as Morsi supporters tried to storm local government buildings or military facilities, battling police or Morsi opponents. At least 30 people were killed throughout the day in Egypt, with 210 wounded, Heath Ministry official Khaled el-Khatib told The Associated Press.
Islamists descended on anti-Morsi rally, opening fire with guns in the Mediterranean coastal city of Alexandria, where at least 12 people were killed, mostly Morsi opponents, emergency services official Amr Salama said. One man was stabbed and thrown from the roof of a building by Morsi supporters after he raised an Egyptian flag and shouted insults against the ousted president, according to an Associated Press reporter at the scene.
Five policemen killed by militants in shootings around the Sinai city of el-Arish, according to security officials speaking on condition of anonymity because not authorized to talk to the press.
The U.S. State Department condemned the violence and called on all Egyptian leaders to denounce the use of force and prevent further bloodshed among their supporters.
"The voices of all who are protesting peacefully must be heard -- including those who welcomed the events of earlier this week and those who supported President Morsi," State Department spokeswoman Jen Psaki said in a statement. "The Egyptian people must come together to resolve their differences peacefully."
Col. Ahmed Ali, a spokesman for the armed forces, said the Muslim Brotherhood was trying to "pick a fight" with the army and "drag it to a clash in order to send a message to the West that what happened in the country is a coup and that the military is cracking down on the peaceful protesters."
That mirrored a statement from an umbrella group of Morsi opponents -- including the National Salvation Front and youth groups. The group urged the public to take to the streets immediately "to defend popular legitimacy" against what they called a "malicious plot" by the Brotherhood.