Colombo: The arrest of retired General Sarath Fonseka, Sri Lanka's former Chief of Army Staff and opposition political candidate in Sri Lanka's recently held presidential election, escalates post-election repression, Amnesty International said on Monday.

Sarath Fonseka was arrested late Monday evening and will reportedly face a military Court Martial on charges that he revealed military secrets and plotted the assassination of President Mahinda Rajapaksa.

"Sarath Fonseka's arrest continues the Rajapaksa government's post-election crackdown on political opposition," said Sam Zarifi, director of Amnesty International's Asia-Pacific programme.

"After the military defeat of the LTTE and a major election victory, President Rajapaksa should steer the country toward a better human rights record. Instead, we're seeing less and less tolerance for criticism."

The timing of the arrest is troubling given reports that Sarath Fonseka had announced earlier in the day that he was prepared to testify before an international court on war crimes charges against the Sri Lanka government.

Since his defeat in the election, several of Sarath Fonseka's key supporters have been arrested. Journalists with the state media suspected of supporting the opposition candidate have also faced threats and violence.

Allegations and counter allegations of responsibility for violations of human rights and humanitarian law featured prominently in the run-up to the election.

Sarath Fonseka was quoted in the press in December accusing the President's brother, Sri Lanka's Secretary of Defence, Gotabhaya Rajapaksa of ordering the executions of surrendering LTTE leaders at the end of the war in May 2009. He later retracted his accusations.

"Allegations of war crimes in Sri Lanka should be subject to an independent international investigation," said Sam Zarifi.

"Sarath Fonseka was commander of the armed forces during a period when Sri Lanka's army was accused of violating humanitarian law, including firing heavy weaponry into an area packed with civilians. Fonseka faces credible allegations of war crimes and should also be subject to investigation and accountability."(EOM)