Sri Lankan newspapers carry the news of the arrest of defeated presidential candidate Gen. Sarath Fonseka, who is now charged with plotting to overthrow the government. (Eranga Jayawardena/Associated Press)

Sri Lankan president Mahinda Rajapaksa dissolved parliament Tuesday, setting the stage for new elections a day after authorities arrested his chief rival and the leader of the opposition, Gen. Sarath Fonseka.

"The elections will be held on April 8 and the new parliament will convene on April 22," Chandrapala Liyanage, a media officer at the president's office, told Reuters.

Sri Lankan President Mahinda Rajapaksa returns on Tuesday to Colombo, the country's capital, after an official visit to Russia. (Sanka Gayashan/Associated Press)

The dissolution follows Rajapaksa's sweeping victory at the polls in January over his former army chief, who had defected to the opposition.

Fonseka, who led government troops in their crushing defeat of Tamil Tiger rebels in 2009, was dragged out of his office Monday by military police and arrested on charges he plotted to overthrow the government while running the army. He has repeatedly denied similar accusations lobbed at him since the election.

Once allies, now foes

One-time allies, Fonseka and Rajapaksa were both considered heroes by Sri Lanka's Sinhalese majority for ending the quarter-century civil war.

More than 7,000 civilians were killed in the final months of the fighting that crushed the rebels last spring. Human rights groups have accused the military, which was led by Fonseka at the time, of shelling hospitals and heavily populated civilian areas during the fighting, and the rebels of holding the local population as human shields.

The relationship between Rajapaksa and Fonseka deteriorated after hostilities ended, and Fonseka led the opposition's attempts to unseat the president in an election on Jan. 26. Rajapaksa won the election by 17 percentage points.

Fonseka wary after election

Since the Jan. 26 election, Fonseka has complained that the government was attempting to arrest him on trumped up charges. Even as returns came in, troops surrounded the hotel where he was staying, in a massive show of force.

Anoma Fonseka tells reporters outside her Colombo home that military police dragged her husband from his office 'like an animal.' (Eranga Jayawardena/Associated Press)

Security forces later raided his office and arrested at least 15 of his staff. A number of military officers, who the government said were considered to be a threat to national security, have been fired.

The opposition has rejected the results of the presidential election, accusing the government of stealing more than one million of Fonseka's votes during the tallying process, and said it will challenge the numbers in court.

The opposition has also accused the government of a campaign of threats, intimidation and illegal imprisonment of its supporters and activists.

Military denies accusations

Rajapaksa' and his party are hoping to secure a two-thirds majority in parliament, giving them the absolute majority and entrenching their grip on power.

Fonseka's wife, Anoma, told reporters Tuesday that she has not been allowed to meet her husband or told where he is being held.

"He was dragged like an animal," Anoma said. "Is this what he gets for ending a 30-year war?"

Military spokesman Maj.-Gen. Prasad Samarasing has denied that Fonseka is cut off from family or friends, adding that the former commander is not even in a cell.