An explosion tore through a polling station and gunfire nearby killed a soldier in Yemen on Monday, the eve of a presidential vote to replace Ali Abdullah Saleh after a year of mass protests and spreading anarchy.
A spate of violence in south and east Yemen underlined the challenges Saleh's successor will face in seeking to prevent Yemen from becoming a failed state and draft a new constitution that would underpin multi-party elections in two years' time.
Interior Minister Abdul Qader Qahtan said in the capital Sanaa that security measures were in place but some violence in the southern province of Abyan, a stronghold of al Qaeda militants, was unavoidable.
There are preventive security measures to confront any contingency ... to confront any group that may attack people, Qahtan told a news conference. Abyan still has many districts under the control of al Qaeda, there are security failures ... and an explosion here and there is expected.
The explosion at the Aden polling station caused no casualties but one soldier was killed and another was injured when unidentified gunmen opened fire on an army patrol in the vicinity. It was unclear if the two incidents were related.
Southern secessionists seeking to revive a socialist state that Saleh united with the north in 1990 oppose Tuesday's vote, which has been touted by diplomats as a turning point for the country following a year of political upheaval.
In another southern province, Dalea, troops opened fire on an anti-election rally, killing one protester and wounding nine, a leader of the Southern Movement said.
A local official said the march, which was heading in the direction of the former border between north and south Yemen some 10 km (six miles) away, was unauthorized and protesters waving southern flags had shot at soldiers, wounding one.
Southerners, who accuse the north of usurping their resources and discriminating against them, have said they will boycott the election because it confers legitimacy on a political process to which they were not party.
Residents of Dalea said armed secessionists had set up checkpoints on the main roads to prevent ballot boxes from being delivered to polling stations.
As well as increasingly vociferous secessionists, Islamist militants suspected of links to al Qaeda have exploited weak central government control to expand their foothold in the south, seizing several towns over the past year.
Unidentified gunmen attacked a polling station in the city of Sioun in the eastern province of Hadramout, besieging it for several hours until security reinforcements arrived to disperse them, killing one and arresting two in the ensuing clashes, a local official said.
The fact that Vice President Abd-Rabbu Mansour Hadi will be the only candidate in the election, under a power transfer deal brokered by Yemen's Gulf neighbours, has raised concern about a low turnout that would curb his legitimacy.
The vote would make Saleh, now in the United States for further treatment of burns suffered in a June assassination attempt, the fourth Arab autocrat to leave office in a year after revolts in Tunisia, Egypt and Libya.
But prospects for a transition towards stable representative government remain uncertain at best given Saleh's vow to return home to lead his party anew, a split in the military, al Qaeda militants entrenched in the south, a Houthi Shi'ite Muslim revolt in the north and a secessionist movement in the south.
The new government should more actively engage with youth, the Houthis and the Southern Movement. The political process will remain in jeopardy if these constituencies remain outside the political process, said U.N. Yemen envoy Jamal Benomar.
In a speech late on Monday, Hadi said Yemen had returned from the brink of collapse and called on the splintered military to help unify the Arabian Peninsula state, where chaos would threaten nearby oil shipping lanes crucial to the world economy.
In the past months Yemen has passed through unprecedented hardship, to the point where the most optimistic of observers expected it to become as fragmented, splintered and destroyed as Somalia, Hadi said.
We cannot talk about a stable nation without returning life to its natural state and removing the phenomena which have appeared, beginning with the split in the army.
Tuesday's vote is part of a deal hammered out by the six-nation Gulf Cooperation Council, anxious to avert a slide into lawlessness on their doorstep.
Backed by the United States, the United Nations and European Union, the deal envisages a new constitution and a referendum paving the way for a multi-party election in two years.
But Hadi's proximity to Saleh and his involvement in a process conceived by diplomats has alienated the Yemeni street, where thousands have camped in shabby tent cities demanding Saleh's removal.
The deal's offer of immunity to Saleh from prosecution over the killing of protesters has only deepened those suspicions.
The elections are a political scenario mapped out in the GCC initiative but in its essence it is irrelevant to the true ideals of democracy, said Rana Jarhoum, 29, development worker. Hadi is going to be elected anyway.
Many also suspect that Hadi will be no more than a caretaker, put in place by Saleh, who has vowed to return after the vote and lead his General People's Congress (GPC) party.
Members of Saleh's inner circle retain pivotal positions of influence, not least his son Ahmed Ali, who commands the Republican Guards, and Yehia, his nephew, who heads the Central Security Forces. They are locked in a stand-off with tribal leader Sadeq al-Ahmar and dissident General Ali Mohsen.
The continuation of a divided military cannot be sustained. We have to have a reintegrated and reunified military leadership, said U.S. Ambassador Gerald Feierstein.
TROUBLE IN THE NORTH
A brewing conflict in the north could also complicate any return to stability and tap into longstanding concerns on the Arabian Peninsula that Shi'ite power Iran was trying to exploit Yemen's instability to spread its Islamic revolution.
We do see Iran trying to increase its presence here, in ways that we believe are unhelpful to Yemen's stability and security, Feierstein told Reuters in an interview.
Iran denies meddling in Yemen.
The Shi'ite Houthi rebels, who draw their name from a tribal leader, have effectively carved out their own state-within-a state thanks to a weakened central government.
The biggest fear is that Yemen's north becomes the stage for a proxy war between Iran and Saudi Arabia, backed by the United States. Saudi Arabia, the world's No. 1 oil exporter and close U.S. ally, has accused Iran of fomenting unrest among Shi'ite populations in its east and in neighbouring Bahrain.
(Additional reporting by Isabel Coles in Dubai and Tom Finn in Sanaa; Writing by Reed Stevenson; Editing by Mark Heinrich)