COLOMBO - U.S. authorities allowed Sri Lanka's military chief to return home without being questioned over human rights violations in the last months of the country's 25-year civil war, the Foreign Ministry said on Wednesday.

The government on Monday had asked U.S. authorities not to question General Sarath Fonseka, the Chief of Defense Staff and a U.S. permanent resident, who led the army to victory over the Liberation Tigers of Tamil Eelam (LTTE) in May.

The U.S. Department of Homeland Security had asked Fonseka to attend an interview on Wednesday in Oklahoma, where he was visiting his daughters.

Sri Lanka feared U.S. authorities might force him to give evidence against Defense Secretary Gotabaya Rajapakse -- a naturalized U.S. citizen and a brother of the Sri Lankan president -- over alleged human rights violations.

He was not subjected to any questioning prior to his departure by the United States Department of Homeland Security or any other agency of the United States government, Sri Lanka's Foreign Ministry said in a statement.

The ministry appreciates the receptive and constructive attitude adopted by the U.S. authorities, which in turn allowed General Fonseka to leave the U.S. without any damage to the national interest of Sri Lanka and to the dignity of his office.

On Monday, Foreign Minister Rohitha Bogollagama said General Fonseka cannot legally share privileged information he may have acquired in the exercise of his official duties with third parties without the prior approval of the Sri Lanka authorities.

Jeff Anderson, a spokesman for the U.S. embassy in Colombo, declined to comment and said: Still nothing to say.

The department's Immigrations and Customs Enforcement division would normally have authority only to probe a matter related to Fonseka's prospective U.S. citizenship as a green card holder and not any possible human rights violations.

Fonseka and Gotabaya Rajapakse led the government campaign that defeated the Tamil Tigers and killed their leaders in May in a bitter end to one of Asia's longest-running insurgencies, which aimed to create a separate homeland for the island's Tamil minority.

Fonseka's name has now surfaced as a potential presidential contender to President Rajapakse, speculation opposition parties have been happy to fan against the incumbent's enormous post-war popularity.

Sri Lanka faces heavy Western pressure over its human rights conduct in the final phase of the war.

The United Nations on October 22 suggested an external probe similar to Gaza on war crimes, while the European Union is considering whether to withdraw a trade concession that helps Sri Lanka's top export, garments.

But the government has said there was no rift between Fonseka and Rajapaksa, who promoted the army commander to the Chief of Defense Staff in July, which many analysts saw as neutralizing the wide powers Fonseka had in wartime.

(Editing by Bill Tarrant)