Colombo, Feb 9 (DPA) Sri Lanka former army commander General Sarath Fonseka, who spearheaded the final phase of military operations against Tamil rebels, was arrested with officials accusing him of conspiring to topple the government.

News of the arrest was first divulged by a military spokesman Major General Prasa Samarasinghe, who said Fonseka was arrested Monday by military police at his political office in the capital for a military offence.

Director General of the Media Centre for National Security, Lakshman Hulugalle said that Fonseka would face charges in a military court of conspiracy against the government.

Hulugalle said that Fonseka was arrested for discussing with the opposition to conspire to topple the government and creating divisions within the army when he was the commander.

Fonseka had unsuccessfully contested last month's presidential elections.

Earlier Monday, the government claimed that Fonseka along with the opposition planned to assassinate President Mahinda Rajapaksa who was elected for a second term in the Jan 26 presidential elections.

Soon after the news of the arrest, opposition politicians who backed him at the presidential elections arrived at his office to show their solidarity.

Fonseka was planning to contest the parliamentary elections set to take place in April.

The ex-army commander was praised by the government for his role in defeating the Tamil rebels of the Liberation Tigers of Tamil Eelam (LTTE) after killing the entire rebel leadership including its leader Velupillai Prabhakaran in May last year.

But soon after, Fonseka fell out with the government after he was asked to step down from the commanders position and told to take up a posting as the Defence Chief of Staff, a ceremonial post.

Fonseka entered politics after he stepped down from the Defence Chief of Staff position in November and contested elections with the backing of three of the main political parties including the main opposition led by the opposition leader in Parliament Ranil Wickremesinghe.

The ex-army chief was able to secure only 40 percent of the vote against 58 percent for Rajapaksa.

Since the elections, more than 20 personal staff of Fonseka, including a retired Major General and 15 ex-military personnel, have been arrested.

Hours before Fonseka was arrested he met with family members of those who have been arrested.

'Don't think we have forgotten the families of those who have been arrested. Our lawyers are closely monitoring their cases,' he said.

Rajapaksa, who is on a three-day official visit to Russia, is due back in the country Tuesday morning.