COLOMBO, Dec. 28 (Xinhua)-- Sri Lanka's main Muslim party, the Sri Lanka Muslim Congress (SLMC), on Sunday became the latest crossover to the opposition as President Mahinda Rajapaksa battles to win a third term in power.

SLMC leader Rauff Hakeem made a formal statement of his crossover to reporters and announced he had also resigned as the Justice Minister of Rajapaksa's government. "I have already sent my resignation letter to the president,"he confirmed at a media gathering.

The decision to back the opposition candidate Maithripala Sirisena came after several rounds of discussions including one on Saturday where the final breakthrough took place. Analysts indicate the party was not satisfied with the government's attempts to safeguard minority rights.

Relations between the government and the Muslim minority, which makes up about 10 percent of Sri Lanka's 20.4 million population, have become increasingly frosty due to the presence of hardline Buddhist groups that have emerged over the last two years.

Earlier this year, Hakeem accused extremist groups of inciting communal violence in the southern towns of Aluthgama and Beruwala that left at least two people dead as well as dozens of houses and shops torched.

The SLMC is the second major Muslim party to join the opposition after Industry and Commerce Minister Rishad Bathiudeen and his political party, the All Ceylon Makkal Congress (ACMC), crossed over last week.

However, the country's largest minority, which is the Tamil population of about 12 percent, is yet to declare for either candidate.

Rajapaksa was expected to run largely uncontested when he called for snap presidential polls in late November, two years ahead of his second term ending, but an unexpected rival appeared when his former Health Minister Maithripala Sirisena joined the opposition.

His coalition partners, the nationalist Jathika Hela Urumaya ( JHU) front liners, also crossed over along with at least 16 parliamentarians.

The Opposition's rallying cry has been criticizing rampant corruption, nepotism and declining good governance in the country. They have pledged to end the controversial executive presidency in 100 days if elected on Jan. 8.