ADDIS ABABA (Reuters) - A total of 669 people were killed in unrest that gripped Ethiopia for several months until authorities imposed a state of emergency last October, according to an investigation report presented to parliament on Tuesday.

The Horn of Africa country declared six months of emergency rule after more than a year of violent protests in its Oromiya, Amhara and SNNP regions. Demonstrators in the three areas say the government has trampled on their political rights.

Ethiopia has faced criticism from abroad as well as at home over its authoritarian approach to economic development, though the government has also presided over stellar rates of growth.

The Ethiopian Human Rights Commission - a body mandated by parliament to investigate the violence - presented its findings on Tuesday and acknowledged that security forces had taken disproportionate measures in some areas.

The report said 462 protesters and 33 security personnel had been killed in the unrest that engulfed 91 towns in the Oromiya region alone. The protesters opposed having their land incorporated into the boundaries of the capital Addis Ababa.

Commission head Addisu Gebregziabher told parliament that security forces had been “negligent” when firing teargas at protesters during a religious festival, triggering a stampede that killed scores.

In the Amhara region, 110 demonstrators and 30 security officials were killed in clashes sparked by the arrest of activists campaigning over disputed territory, the report said.

Tensions there have simmered for around 25 years over the status of Wolkayt district, which the protesters say was illegally incorporated into the neighboring Tigray region to the north.

That dispute is particularly sensitive because it runs counter to a division of Ethiopia along ethnic and linguistic lines, imposed by the core of the current ruling EPRDF coalition when it came to power in 1991.

The report said another 34 people died in the SNNP region which lies to the south of Addis Ababa.

Ethiopia is an important Western ally against Islamist militants in neighboring Somalia as well as an increasingly important economic player in a fragile region.

In October Ethiopia accused “elements” in neighboring Eritrea, in Egypt and elsewhere of being behind the wave of disturbances. It has since extended the nationwide state of emergency by four months.