Egyptian people on Saturday morning went to polling booths to vote in the first stage of the referendum on a draft constitution, which has recently caused controversy in the country and led to bitter division between liberals and Islamists.

Four people have been injured so far due to overcrowding, the health ministry was quoted by official MENA news agency as saying.

One injury case was reported in Cairo, with three others in Alexandria, Sharqeya and Daqahlya, respectively, said health ministry spokesman Ahmed Omar, adding all are in stable condition.

There have been rumors that a judge died while overseeing a polling station in the governorate of Daqahlya on Saturday morning, but state-run Nile TV denied the news after communicating with chief of judges supervising the vote in the governorate.

The voting, which began at 8:00 a.m. local time (0600 GMT), was originally set to end at 7:00 p.m. (1700 GMT), has been extended to 9:00 p.m. (1900 GMT).

Great turnout was witnessed in the involved 10 governorates, including Cairo and Alexandria, with 26 million people eligible to cast ballots.

Ahamed Khader, a 76-year-old senior citizen voting at Cairo's suburb of Maadi, told Xinhua that "exercising the right of voting is a duty of every citizen," expressing hope that the country would have a brighter future via this referendum.

Outside the polling station where Khader voted, hundreds of voters lined up, as soldiers and policemen, along with plainclothes men, are securing the voting progress. Egyptian President Mohamed Morsi has given the army the power to arrest civilians, calling them to help the police maintain the security of the referendum.

A veiled woman named Samiha told Xinhua that she has ticked the "Yes" on the ballot, which is signed as a red circle. The "No" is signed as a blue one.

The referendum was planned to run in two stages, according to a republican decree issued by Morsi on Wednesday.

The first stage of the referendum will cover the governorates of Cairo, Alexandria, Daqahlya, Gharbeya, Sharqeya, Assiut, Souhag, Aswan, Southern and Northern Sinai, while the second phase will be held a week later in the rest of the country.

About 6,376 polling stations were set for the first stage, including 175 general stations, MENA reported.

A senior officer from the Interior Ministry confirmed to MENA that the situation of all stations was normal under intensive security measures.

The Higher Election Commission said Saturday that it had not received, so far, any complaints on irregularities in the 10 governorates of the first voting stage, MENA reported.

A member of a nongovernmental human rights organization, who named himself Ali, said that he was worried about potential confrontations during the voting process.

Ali said the current situation came more complicated than the parliamentarian and presidential elections which he had also taken part in supervising.

In Zamalik, downtown Cairo, long queues were seen outside polling stations, and voters were well organized according to age and gender.

In the Mediterranean city of Alexandria, voting took place amid tension due to Friday night's clashes between supporters and opponents of the constitution that continued until early hours of Saturday morning. Still, no armored vehicles or heavy equipments were seen outside polling stations, with only policemen and navy officers securing polling stations.

Meanwhile, some stations' voting time were forced to be postponed, because the overseeing judges came late, which reflected the problem of allocation of judges.

Chairman of Egypt's Judges' Club Ahmed al-Zend said Tuesday that "90 percent of Egyptian judges refuse to supervise the referendum."

Al-Zend added in a meeting held by the club that the draft constitution violates the independency of judiciary, criticizing a movement of independent judges named "Judges in the interest of Egypt" for approving referendum supervision.

Morsi has cast his ballot at a high school in the Misr al- Gedida district where the presidential palace is located, MENA reported.

Morsi issued a new constitutional declaration last Sunday, annulling the previous one issued on Nov. 22 designed to expand the president's powers by making all his decrees issued since he came into office final and above judicial appeal.

The new constitutional declaration also ruled that if the new constitution was voted down in the referendum, the president would call for electing a new assembly through direct ballot to draft a new constitution. The new 100-member panel will be elected within three months after the announcement of referendum results.

But the new draft has not shaken the opposition. Fresh demonstrations held by Morsi's supporters and opponents raged recently in different districts in Cairo ahead of the disputed constitutional referendum.

Egyptian former diplomat Mohamed El-Baradei, leader of the main opposition bloc, the National Salvation Front, renewed his call Saturday for voting "No" to the draft constitution, despite their long-time calls for postponing the referendum.

El-Baradei said via his account of twitter "to all Egyptians, listen to the sane voice, and vote No to the draft constitution in order to salvage the country, and bring victory to it."

For its part, Egyptian foreign minister announced that the deadline of constitutional referendum abroad had been extended to 8 p.m. local time (1800 GMT) on Dec. 17, rather than Saturday.

About 589,000 Egyptian expatriates are expected to go to the Egyptian embassies and consulates overseas to cast their ballots in a voting process started on Dec. 12.

Late in November, 85 members of the beleaguered Constituent Assembly approved the draft constitution after a 17-hour marathon vote. Morsi then called on Egyptians to cast their votes in the referendum.