Ethiopian opposition leaders held after meeting rights group

* Leaders had met Amnesty International

* Held under controversial anti-terrorism law

* Government says they accused of ties to OLF rebels

By Barry Malone

ADDIS ABABA, Sept 1 (Reuters) - Two Ethiopian opposition leaders are being held by police after meeting an Amnesty International delegation and foreign reporters investigating rights abuses, their party said late on Wednesday.

The government says they are "terrorism" suspects who can be held for 28 days without charge on suspicion of being linked to Oromo Liberation Front (OLF) rebels, who have fought since 1993 for more autonomy for the coffee-growing Oromia region.

Ethiopia introduced anti-terrorism legislation last year that has been criticised by foreign rights groups and Western donors.

Party officials from Ethiopia's main opposition coalition, Medrek, told Reuters that the men -- Bekele Gerba who is deputy leader of the Oromo Federalist Democratic Movement (OFDM) and Olvana Lalesa who is chief of office for the Oromo People's Congress (OPC) -- had last week met a delegation from international rights group Amnesty International.

Opposition officials told Reuters the men may have co-operated with a BBC investigation into food aid being denied to members of the opposition in the Horn of Africa country.