Colombo, Jan 13 (Agencies): Sri Lanka's powerful Defence Secretary was on Thursday ordered to appear before a High Court to testify in the controversial 'white flag' case where the detained former army chief reportedly claimed that troops shot dead surrendering Tamil leaders during the final stages of ethnic conflict in May 2009.

The Colombo High Court on Thursday ordered Gotabhaya Rajapaksa to appear before it on January 25 to testify in on controversial 'white flag' case against former Army Commander and Democratic National Alliance (DNA) leader Sarath Fonseka, who sentenced to 30 months of hard labour for irregularities in military purchases, ColomboPage online said.

Fonseka was accused of disclosing state secrets for allegedly telling The Sunday Leader newspaper in an interview that Defence Secretary Rajapaksa had ordered the shooting of senior LTTE cadres who tried to surrender to the security forces carrying white flags during the final stages of the war.

The Defence Secretary is the fourth witness to testify in the trial, the report said.

Fonseka faces a plethora of court cases and is also appealing against two courts martial convictions which stripped him of his rank and pension.

The former four-star General, the key military figure who led the armed forces to a historic victory over the Tamil Tigers, fell out with his former commander in chief, President Mahinda Rajapaksa and ended up challenging him at the January polls.

The Lankan military crushed the rebels in May  2009 and ended the ethnic conflict that killed between 80,000 and 100,000 people.

The LTTE waged a bloody three-decade civil war for a separate state for the Tamils of Sri Lanka, alleging discrimination against the minority community at the hands of the majority Sinhalas.