CAIRO – Egypt's opposition coalition said Sunday it was moving toward forming a single political party to challenge Islamists, whose more disciplined ranks have dominated the ballot box since last year's revolution. Members of the opposition National Salvation Front, whose differences have split the non-Islamist vote, pledged to keep up the pressure on President Mohamed Morsi, including through peaceful protests. Liberals, socialists and other factions that united under the banner of the Front campaigned unsuccessfully for a “no” vote in a referendum on a new constitution which, according to an unofficial tally by Morsi's Islamist backers Sunday, secured 64 percent approval on turnout of about a third of the 51 million eligible voters. “The Front is very cohesive and the Front is in agreement that it will lead all battles together,” Mohamed Abul Ghar, head of the Egyptian Social Democratic Party and a leading member of the Front, told a news conference after the referendum. “Not only that, but the parties inside the Front have taken advanced steps to form a big party inside the Front,” he said. A statement from the Front said it had learnt “useful lessons” during the referendum. But it will have little time to organize, as a parliamentary election is due to be held in about two months. Egypt's opposition said Sunday it will appeal the referendum. Polling “fraud and violations” skewed the results of the two-stage referendum, the final leg of which was held Saturday, the National Salvation Front charged. “We are asking the (electoral) commission to investigate the irregularities before announcing official results,” a Front member, Amr Hamzawy, told a Cairo news conference. “The referendum is not the end of the road. It is only one battle,” said another member, Abdel Ghaffar Shokr, reading from a Front statement. “We will continue the fight for the Egyptian people.” Germany immediately backed the call for a transparent investigation into the results. Foreign Minister Guido Westerwelle said: “The new constitution can only meet with acceptance if the process of its adoption is beyond reproach.” But Westerwelle said it was “not the power of the street but rather the spirit of compromise and tolerance that should determine the way forward for Egypt.” Egyptian state media and Morsi's supporters in the Muslim Brotherhood said the constitution was passed with the support of nearly two-thirds of voters, based on unofficial tallies. A member of the national electoral commission, Mohamed El-Tanobly, said that “no official date has been fixed” for the publication of the final referendum results. The state news agency MENA had reported they would be released Monday. Opposition to the charter have fuelled demonstrations for the past month, some of them violent, such as clashes that wounded 62 people in Egypt's second city of Alexandria on Friday, the day before the final round of voting. The army has deployed troops to reinforce police since December 5 clashes outside the presidential palace in Cairo killed eight people and injured more than 600 others. Morsi and Islamists backing the charter say it is necessary to restore stability after the early 2011 revolution that toppled president Hosni Mubarak. But the opposition sees the new constitution as a wedge to usher in creeping Islamic law through a weakening of human rights, particularly women's rights, and undermine the independence of the judiciary. – Agencies