Sri Lankans faced a tense wait Friday for the result of a bitterly contested election that pitted South Asia’s longest-serving leader against a former minister who has become a symbol of resentment over corruption.

Voters turned out in large numbers on Thursday for the tightest presidential election Sri Lanka has seen in decades.

President Mahinda Rajapakse had seemed assured of victory when he called snap polls in November seeking an unprecedented third term, five years after crushing a violent separatist rebellion that had traumatised the country for decades.

But he has become unpopular in recent years, dogged by accusations of increasing authoritarianism and corruption and a failure to bring about post-war reconciliation.

His health minister Maithripala Sirisena’s surprise decision to defect from the government and stand against him galvanised disparate opposition groups, creating a far closer contest than had been expected.

Sri Lanka does not conduct exit polls, but early partial results on Friday showed that Sirisena had taken a marginal lead over Rajapakse, with about 56 percent of the nearly 600,000 votes counted so far. Just over 75 percent of the 15.04 million electorate cast their vote.

Despite sporadic campaign violence including the death of one opposition party worker, the vote passed off largely peacefully, although there were some reports of intimidation in Tamil areas.

Police said they had made 175 election-related arrests, but described the polls as some of the most peaceful in Sri Lanka’s recent history.

The president had come under international pressure after opposition reports that he was mobilising the military, with top US diplomat John Kerry this week urging him to ensure the election was peaceful and credible.

The polls came days before a visit to the island by Pope Francis which some Catholic leaders had said should be cancelled in the event of violence.

Election monitors said large numbers of people had voted in the heavily militarised former war zones of the north and east, whose largely Tamil population had boycotted previous national elections.

Tamil leaders said two explosions in the northern Jaffna peninsula were an attempt to deter voters, but there were no casualties and voting continued.