CAIRO: Egypt's opposition said on Sunday it will appeal a referendum that voted in a new constitution backed by ruling Islamists, vowing to keep up a struggle that has spawned weeks of protests and damaging instability.
Polling "fraud and violations" skewed the results of two-stage referendum, the final leg of which was held on Saturday, the National Salvation Front said.
"We are asking the (electoral) commission to investigate the irregularities before announcing official results," scheduled for Monday, 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 Ghaffer Shokr. "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."
State media and President Mohamed 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.
Opposition to the charter fuelled demonstrations for the past month, some of them violent, such as clashes that wounded 62 people in the 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.
Morsi and Islamists backing the charter say it is necessary to restore stability after the early 2011 revolution that toppled 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.
It accuses Morsi of steamrolling through the referendum without consensus on the charter, and argues that a low voter turnout of around 32 percent undermined the plebiscite's legitimacy.
Approval of the constitution would trigger parliamentary elections in two months' time to replace an Islamist-dominated assembly that was dissolved by Egypt's constitutional court before Morsi's election in June.
In the meantime, all legislative business is being handled by the senate, also under the sway of Islamists.
In a gesture towards "national dialogue," Morsi on Saturday appointed 90 additional senators, including eight women and 12 Christians.
The US government, which sees Egypt as a pillar of its Middle East policy and provides Cairo with $1.3 billion annually in military aid, has deliberately avoided public comment on the crisis.
But the Republican chairwoman of the Foreign Affairs Committee in the US House of Representatives, Ileana Ros-Lehtinen, on Saturday called the vote "a defeat for the Egyptian people" at the hands of "an Islamic dictatorship."
She said: "We must use our aid as leverage to promote democratic reforms, support freedom of religion, and enshrine the protection of minority communities."