Colombo: Voting in Sri Lanka's bitterly fought presidential election closed Thursday with monitors and officials saying turnout was high, despite some reports of intimidation.

With final tallies still being prepared, election officials estimated participation reached more than 70 percent in most places in the first seven hours of voting.

Voter numbers were unusually high in the Tamil-dominated north and east of the country, which have boycotted national elections in the past, the officials said.

There were no major reports of violence, although the Campaign for Free and Fair Elections (CaFFE), a private monitoring group, said a small number of voters had been prevented from casting their ballots.

Election monitors reported two large explosions in the south and east that initially caused panic, but there were no casualties and voting was unaffected.

"A high turnout usually favours the opposition," said CaFFE head Keerthi Thennakoon.

The Tamils could decide the election if, as looks likely, the majority Sinhalese vote is split evenly between incumbent Mahinda Rajapakse and the main opposition presidential candidate Maithripala Sirisena.

Sri Lanka's Tamil minority accounts for about 13 percent of the population.