Hassan al-Nuri

Syrians are voting in a presidential election on Tuesday, with incumbent Bashar al-Assad in pole position to win a third term.

The opposition has labeled the vote as a "farce", manipulated by the ruling party. Polling stations have only been opened in the government-controlled areas, while people in the rebel-held regions will not be able to have their say, the BBC reports.

Syrians voted as fighting raged June 3 in a presidential election in which Bashar al-Assad is looking to tighten his grip as his forces battle rebels in a devastating three-year war.

Assad is facing two little-known challengers and is expected to win, despite a massive rebellion and a war which the U.N. has warned is likely to drag on even longer as a result of the vote.