COLOMBO (Reuters) - Sri Lankan President Mahinda Rajapaksa and his former health minister, Mithripala Sirisena, submitted nominations on Monday to contest next month's presidential election, which is expected to be a tight race between the one-time party allies.
The election commissioner approved 19 nominations to contest the poll, which Rajapaksa - president since 2005 - called early with an eye to winning an unprecedented third term.
But Rajapaksa faces criticism over corruption, nepotism and intervention in foreign services and the judiciary, charges he has rejected.
He is also at loggerheads with Western nations which say that war crimes were committed during the final phase of the war against Tamil Tiger rebels, and which have complained about the slow pace of reconciliation with minority Tamils in the island's north.
A firm believer in astrology, Rajapaksa set off at an auspicious time to hand in his nomination after religious observations at his official residence, according to state TV.
He is still popular among rural Sri Lankans, who account for 70 percent of the population, after winning the 26-year war against the Liberation Tigers of Tamil Eelam in 2009. Supporters along the road cheered as he went by on Monday, chanting "People's leader".
"We are expecting a victory, a great victory," Rajapaksa told reporters after handing over his nomination papers.
Sirisena defected last month to contest as a common opposition candidate backed by the United National Party (UNP) and Rajapaksa's predecessor, Chandrika Bandaranaike Kumaratunga.
"I'm confident that the victory we will get is a great victory. I will implement the rule of law, democracy and make a peaceful country by chasing away family rule and corrupt rule," Sirisena told reporters.
Rajapaksa's core Buddhist vote base may be split by Sirisena's challenge, but analysts say he still has an edge.
"It (the government) is likely to use its hold over the state machinery to hinder opposition campaigners and intimidate opposition voters," Eurasia Group's Sasha Riser-Kositsky said in a research note.
"Moreover, the government is likely to use the military, firmly under control of the president's brother, Defence Secretary Gotabaya Rajapaksa, to intimidate opposition voters."
Writing by Shihar Aneez; Editing by John Chalmers and Nick Macfie