The U.S. government said on Wednesday that the Egyptian presidential election is an "important milestone" for the transition in the Middle East country.

"Today does mark the start of a first round of Egypt's historic presidential elections. It's a very important milestone for Egypt' s transition," State Department spokeswoman Victoria Nuland said at a briefing.

Nuland's remarks came as Egyptians went to polls on Wednesday to elect a new president after the fall of ex-President Hosni Mubarak last year.

Stunned by the "long list" of candidates, the spokeswoman expected that there will be a presidential runoff following this round of polls.

Nuland also called on Egypt's military authorities, the Supreme Council of the Armed Forces (SCAF), to "keep their word" in ceding power after the election.

There are about 50 million eligible Egyptian voters, who will select one from the 12 presidential candidates. Top hopefuls include former Arab League chief Amr Moussa, Islamist Aboul Fotouh, Freedom and Justice Party chairman Mohamed Morsi and former Prime Minister Ahmed Shafiq and left-wing Nasserist Hamdeen Sabahy.

Analysts say it is unlikely to have a clear winner in the first round as votes will be much divided among popular candidates. The run-off will be held in June. To win the election requires a candidate to win over 50 percent of the votes.

The results of the presidential polls will be announced on June 21. The SCAF, who took over power from Mubarak, is expected to transfer power to the new president by June 30, which marks the end of the transitional period.