Ethiopia has detained 1,200 people over the deadly political violence that broke out a fortnight ago, police say.

These are the first mass arrests since reformist Prime Minister Abiy Ahmed came to power in April.

At least 28 people died in clashes near the capital, Addis Ababa, following the return of exiled leaders of a former rebel group, the Oromo Liberation Front (OLF) on 15 September.

Rights group Amnesty International has called for the prisoners' release.

In addition to those held in connection with the violence, a further 1,400 people were taken into custody following raids on places where people gamble, smoke shisha or chew the narcotic leaf khat.

Most of those have been released, Addis Ababa police chief Maj Gen Degfie Bedi is quoted as saying by the state-linked Fana Broadcasting Corporate (FBC).

Those arrested for the violence have been sent to Tolay military camp, which is known for providing what is called "rehabilitation training", reports the BBC's Habtamu Tibebu from Addis Ababa.

The trouble began on 13 September as OLF supporters placed their flag in parts of the capital. The move was interpreted by some residents as an attempt by the OLF to take control of Addis Ababa.

Rival supporters then clashed leading to the closure of parts of the commercial centre of Addis Ababa.

The violence escalated two days later, leaving 28 people dead, FBC quotes Maj Degfie as saying. (BBC)

•Clashes broke out after the flag of a former rebel group was displayed in the capita. Photo credit: AFP