Bamako (AFP) - Malians were voting on Sunday in a presidential runoff likely to see Ibrahim Boubacar Keita returned to office despite criticism of his handling of the country's security crisis and allegations of election fraud.
The second round is a rerun of a 2013 faceoff that Keita, 73, won by a landslide over former finance minister Soumaila Cisse.
This year's campaign saw fierce attacks on Keita's perceived failure to dampen a wave of jihadist bloodshed and ethnic violence, as well as mounting accusations of vote fraud.
But public enthusiasm has been low and the opposition is fractured.
"We hope the new president does better and knows how to make up for past mistakes," El Hajd Aliou Sow, a retired civil servant, told AFP as he left a group of early-morning voters.
Mali, a landlocked nation home to at least 20 ethnic groups where the majority of people live on less than $2 a day, has battled jihadist attacks and intercommunal violence for years.
After the July 29 first-round vote the pool of candidates was reduced from 24 to two, as Keita was credited with 42 percent of the vote and Cisse, 68, picked up 18 percent.
That vote was peppered by violence and threats from armed groups that led to several hundred polling stations being closed, mainly in the lawless central region.
Security services said Saturday they had disrupted a plot to carry out "targeted attacks" in the capital Bamako on the eve of the runoff.
Several polling stations were again closed in the restive central and northern regions on Sunday due to insecurity.
Voting could not take place in the northern village of Kiname, 120 kilometres (75 miles) from Timbuktu, after "armed men came and took all the voting material to the river bank and set it on fire," a resident told AFP.
"There was no voting in Toguerekotia in the Sossobe district (of the central Mopti region) because of insecurity," the West Africa Network for Peacebuilding (WANEP), which has 150 observers across the country, said in a statement.
Keita cast his vote in the capital Bamako shortly after 0900 GMT and warned against "staged" electoral fraud after accusations of ballot box stuffing and other irregularities.
"How could you stage fraud when you are assured of the support of your people?" Keita said.
Cisse's party told AFP in the early hours of Sunday that ballot papers were already circulating, several hours before polls opened.
But he has failed to unite the opposition behind him, and first-round challengers have either backed the president or refused to give voting instructions.
Local observers said voter turnout was low by the afternoon, WANEP said in a statement.
Voting will close at 1800 GMT and results are expected within five days. Turnout was low in the first round at around 40 percent.
Security has been tightened for the second round, an aide in the prime minister's office said, with 20 percent more soldiers on duty.
This means 36,000 Malian military will be deployed, 6,000 more than two weeks earlier, with a particular focus on the Mopti region in the centre of the country where voting stations had been closed.
The three main opposition candidates mounted a last-ditch legal challenge to the first-round result, alleging ballot-box stuffing and other irregularities. But their petition was rejected by the Constitutional Court.
Outside Mali, the hope is that the winner will strengthen a 2015 accord that the fragile Sahel state sees as its foundation for peace.
The deal brought together the government, government-allied groups and former Tuareg rebels.
But a state of emergency heads into its fourth year in November.
Jihadist violence has spread from the north to the centre and south of the vast country and spilled into neighbouring Burkina Faso and Niger, often inflaming communal conflicts.
France still has 4,500 troops deployed alongside the UN's 15,000 peacekeepers and a regional G5 Sahel force, aimed at rooting out jihadists and restoring the authority of the state.