Regional protests that began last year in Ethiopia have spread across the country, and despite successive crackdowns analysts say dissatisfaction with the authoritarian government is driving ever greater unrest.

Demonstrations began popping up in November 2015 in the Oromia region, which surrounds the capital, due to a government plan to expand the boundaries of Addis Ababa.

The region's Oromo people feared their farmland would be seized, and though the authorities soon dropped the urban enlargement project and brutally suppressed the protests, they badly misjudged the anger it triggered.

Protests have since swept other parts of Oromia, and more recently to the northern Amhara region, causing disquiet in the corridors of power of a key US ally and crucial partner in east Africa's fight against terrorism.

"Since it came to power in 1991, the regime has never witnessed such a bad stretch... Ethiopia resembles a plane going through a zone of extreme turbulence," independent Horn of Africa researcher Rene Lafort told AFP.

Despite what he described as the "state of siege" imposed on the Oromia region in recent weeks, the protests have refused to die down, and demonstrators have been challenging government more and more openly.

- Minority rule -

One rally was even held in Addis Ababa on Saturday, a rare event for the seat of power of a nation ruled by a regime considered among the most repressive in Africa.

More than 140 people were killed when security forces put down the original Oromia land protests, shot or tortured to death, according to rights groups.

A fresh crackdown over the weekend led to the deaths of almost 100 more, according to an Amnesty International toll, with live fire used on the crowds.

"This crisis is systemic because it shakes the foundations of the model of government put into place 25 years ago, which is authoritarian and centralised," Lafort explained.

The protesters have different grievances but are united by their disaffection with the country's leaders, who largely hail from the northern Tigray region and represent less than 10 percent of the population.

Prime Minister Hailemariam Desalegn heads the Ethiopian People's Revolutionary Democratic Front (EPRDF), which won all the seats in parliament in elections last year.

Although he comes from the minority Wolayta people, he is surrounded in government by Tigreans, who also dominate the security forces and positions of economic power.

Getachew Metaferia, professor of political science at Morgan State University in the United States, described the state as "controlled by an ethnic minority imposing its will on the majority," a crucial factor in understanding the protests.

More than 60 percent of the country's almost 100 million people are either Amhara or Oromo.

"There is no fundamental discussion with the people, no dialogue... the level of frustration is increasing. I don't think there will be a return back to normal," the professor added.

The country's rulers have cultivated the skyrocketing growth and rapidly improving health outcomes that have changed the face of a nation whose famines weighed on the world's conscience in 1980s.

But their grip on civil liberties has tightened: Ethiopia ranked 142 of 180 countries in Reporters Without Borders' press freedom index this year, and social media used to organise rallies is regularly blocked by the authorities.

The use of anti-terror laws to jail opposition critics has also provoked ire, combined with more local issues such as the targeting of Amharan politicians campaigning for a referendum on a district absorbed into Tigrean territory.

- Reclaiming freedoms -

The West has largely avoided direct criticism of the country's rights record because Ethiopia is credited with beating back Al-Qaeda-affiliated Shabaab militants in Somalia, but the protests put its allies in an awkward spot.

"Ethiopia's leaders have lost the vision of Meles. They are showing signs of nervousness and don't place trust in their own people," said one European diplomat on condition of anonymity.

After toppling dictator Mengistu Haile Mariam in 1991, Meles Zenawi ruled with an iron fist until he died in 2012, and Hailemariam took over.

More used to its image as an oasis of calm in a troubled region, the government is swift to blame foreign "terrorist groups" for the unrest, usually pointing the finger at neighbouring Eritrea.

Hailemariam last Friday announced a ban on demonstrations which "threaten national unity" and called on police to use all means at their disposal to prevent them.

Merera Gudina, leader of the opposition Oromo People's Congress, said the nebulous movements were not affiliated with traditional political parties and were focused above all on claiming back freedoms the government has long denied.

"We are nine months into this protest. I don't think it will stop," he told AFP. "This is an intifada," he said, using a term which means uprising.