President Samia Suluhu Hassan on Monday named Ali Idi Siwa as her new head of intelligence in a surprise move, replacing Saidi Hussein Massoro who held the position for less than eight months.

In a two-paragraph statement, the Presidential Communications Unit gave no reasons for the abrupt change as Siwa, a former Tanzanian High Commissioner to Rwanda, was sworn-in almost immediately as director general of the Tanzania Intelligence and Security Services (TISS) at a brief State House ceremony in Dar es Salaam.

Massoro was appointed as the TISS boss on January 3 this year after serving for some years as deputy to his predecessor Diwani Athuman. He has now been given ambassador status and could be posted to a diplomatic mission abroad.

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Former President Jakaya Kikwete appointed Siwa as Tanzania's envoy to Kigali in 2014 during a period of frosty diplomatic relations between the two countries.

President Paul Kagame delayed approving the appointment for some months, triggering some speculation that he had rejected Kikwete's choice for the position. It was not until May 2015 that Siwa was finally allowed to present his credentials to the Rwandan leader.

A 46-year Tanzanian civil service veteran (since 1977), Siwa also previously served as a principal foreign affairs officer at Tanzania's missions in the United Arab Emirates (UAE), Russia and Germany.

He was the country's envoy in Kigali from 2015 to 2018, after which he was named as chairperson of the National Social Security Fund (NSSF) Board of Trustees, a position that he held until his latest appointment.