Supporters of Egypt's Islamist President Mohammed Morsi chant slogans and dance with sticks during a rally in Nasr City, Cairo, Egypt, Sunday, June 30, 2013. Thousands of opponents and supporters of Egypt's Islamist president began massing in city squares in competing rallies Sunday, gearing up for a day of massive nationwide protests that many fear could turn deadly as the opposition seeks to push out Mohammed Morsi. AP Photo/Virginie Nguyen Hoang CAIRO (AP) - Hundreds of thousands of Egyptians took to the streets Sunday, some in support of Islamist President Mohammed Morsi and others to call for his ouster. Here is a look at Egypt's current political standoff, what it means and where it could lead: A new youth movement called Tamarod, or Rebel, is spearheading the latest campaign aimed at forcing Morsi from office. The group launched a petition drive around three months ago to collect signatures from Egyptians who want the president to step down. Tapping into growing discontent with Morsi over what his critics allege is his failure to effectively tackle the country's pressing problems, Tamarod claims it has collected more than 22 million signatures. The petitions have no legal weight and have not been independently authenticated, but the tally would be - if verified - nearly twice the number of votes Morsi received a year ago when he narrowly won the presidency. The main collection of opposition groups, the National Salvation Front, has endorsed Tamarod, and parties under the NSF umbrella helped collect signatures. Morsi, who has three years left in his four-year term, says he has no intention of resigning. The Tamarod organizers and opposition figures say protesters will not leave the streets until he does. If both sides stick to their guns, then the standoff could last for days, maybe even weeks. There are other factors at play, however. If the large numbers in Sunday's mass protests are repeated for days, and are later reinforced by strikes and a civil disobedience campaign, the country would grind to a standstill and significantly ratchet up the pressure on Morsi. Still, the Muslim Brotherhood, the fundamentalist group that propelled Morsi to power, has shown little sign of backing down. The group points to Morsi's election victory in a vote that is widely recognized to have been free and fair, and says that forcing Morsi from office will set a dangerous precedent for his successors, an argument Morsi cited in an interview with The Guardian published on Sunday. The only way to challenge Morsi, his supporters say, is through the ballot box. The army chief, Gen. Abdel-Fattah el-Sissi, called on Morsi and the opposition a week ago to reach an understanding and warned that the military would intervene if the country plunges into civil strife. The remarks were the strongest from the military on the nation's political turmoil since Morsi appointed el-Sissi last August. Since those comments, the army has dispatched reinforcements to bases outside cities across the nation and deployed troops backed by armored vehicles outside vital facilities. A secretive institution by nature, the army has not tipped its hand on Egypt's current political standoff. It is considered unlikely that the military will stage a coup to depose Morsi. One possible scenario, however, could see troops coming to the defense of opposition protesters if violence breaks out. Such a move would provide a boost to the anti-Morsi camp and likely embolden many more Egyptians to take to the streets confident they would be protected by the military. On the other hand, the military may see the wave of mass protests as a golden opportunity to get rid of Morsi and the Brotherhood. El-Sissi has not publicly clashed with Morsi, although there have been signs of tension between the two powerful institutions they represent. Some observers say the army has never been comfortable with the president's close ties with Hamas, the Brotherhood's Palestinian chapter that the military has long seen as a threat to stability in Egypt's Sinai Peninsula that borders Israel and the Hamas-ruled Gaza Strip. Intervening would likely leave the military effectively in charge of the country again, much as it was after the 2011 uprising that toppled Hosni Mubarak. The military has been sharply criticized for its record running the country over that nearly 17-month period. Critics have blamed it for mismanaging the transition, and accuse it of committing large scale human rights violations, including torturing detainees and conducting virginity tests on women protesters. The hundreds of thousands who have taken to the streets on Sunday chanting "leave!" have dealt a serious blow to Morsi's claim of holding a popular mandate, and it is difficult to see him riding this out without it taking a toll on his authority. The path Morsi chooses, however, may be heavily influenced by his experience as a longtime member of the Muslim Brotherhood, a secretive group that spent much of the more than 80 years since its creation underground to avoid government crackdowns. The Brotherhood waited eight decades to rule Egypt, and the prospect of relinquishing power now that they have it after so many years of persecution - including the execution of some of its most revered leaders - clearly isn't something the group relishes. Already, Morsi and his Brotherhood supporters have allowed radical Islamist groups with a violent past to take the lead in the campaign to defend the president. They have publicly spoken about "wiping" the protesters and routinely refer to them as "infidels" or paid Mubarak loyalists. But it would be a very risky gamble to unleash them on the opposition, a course of action that could drive Egypt to the brink of civil war, as many have already warned. But there is the potential for violence on the opposition side as well, particularly if the protests drag on and Morsi holds his ground. Some anti-government protests in the past have devolved into clashes. Over just the past week, anti-Morsi protesters have stormed and ransacked several offices of the Muslim Brotherhood and its political arm, the Freedom and Justice party, while clashes in a string of Nile Delta cities and the coastal port city of Alexandria killed at least seven people and wounded hundreds. So far, neither side appears willing to make concessions. Tamarod and the opposition parties insist that early presidential elections are their bottom line. Morsi has insisted, most recently in an interview published Sunday, that he will not step down.