Yemeni President Ali Abdullah Saleh, stepping down after 33 years in office, has urged voters to turn out in large numbers to elect his successor in Tuesday's single-candidate election.

Mr. Saleh said Monday the poll was a moment to move the country towards peace and stability after the year-long popular uprising that forced him from power.

Tuesday's vote is the culmination of a deal — backed by the United States and brokered by Yemen's Gulf neighbors — to replace Mr. Saleh with Vice President Abed Rabbo Mansour Hadi.

Hadi was selected as the sole candidate by a consensus of Mr. Saleh's ruling party and the opposition coalition.

But with the outcome predetermined, there is concern of a low voter turnout that would undermine his mandate. And prospects for a stable, democratic transition in Yemen remain uncertain given Mr. Saleh's vow to return to lead his party anew, a split in the country's powerful military, al-Qaida militants, a secessionist movement in the south and a Shi'ite Muslim revolt in the north.

Violence wracked the country again Monday when attackers in the southern port city of Aden blew up a polling station and gunfire nearby killed a soldier.

The violence underlines the security vacuum in the Arab world's poorest country after a year of political unrest.

President Saleh is the fourth Arab autocrat forced to leave office by the wave of Arab Spring uprisings over the past year. Mr. Saleh is now in the United States for further treatment of burns suffered in a June attack on his presidential compound.

On Sunday, U.S. President Barack Obama offered support for Hadi and said Yemen could be an example of peaceful political transition for other Arab nations.

The message was conveyed by U.S. counterterrorism chief John Brennan, on a two-day visit to Sana'a meant to ensure cooperation would continue with Yemen in fighting al-Qaida's regional branch.