Eritrea has rejoined East African bloc IGAD, four years after it walked out on the body in protest at Ethiopian forces entering Somalia, according to a letter obtained by Reuters. Analysts say Asmara's withdrawal from the Inter-Governmental Authority for Development (IGAD) was the first sign of deteriorating relations between the Red Sea state and regional countries over Somalia, where the Al Qaeda-linked al Shabaab group is battling to overthrow a U.N.-backed government. IGAD member states can suspend and reactivate their membership. Eritrea is the only country to ever do so. "I have the honour to inform you and through you the member states of IGAD that the State of Eritrea has decided to reactivate its membership in IGAD with immediate effect," said a letter from Foreign Minister Osman Saleh sent to Mahboub Maalim, the body's executive secretary. Eritrea said it was "determined" to contribute to regional peace, and cited recent developments such as the independence of South Sudan and the need for a coordinated effort to tackle a regional humanitarian crisis for its re-entry. IGAD is made up of Kenya, Uganda, Djibouti, Ethiopia, Sudan, Somalia and now Eritrea. -- SPA