Yemen has been named the country where the risk of genocide or mass killing rose the most last year, according to a UK-based rights group.

In its annual "Peoples Under Threat" index released on Thursday, Minority Rights Group International (MRG) placed Syria at the top of the list for the third consecutive year.

Highest rated countries (2016) 1. Syria 2. Somalia 3. Iraq 4. Sudan 5. Afghanistan 6. South Sudan 7. Democratic Republic of the Congo 8. Yemen 9. Pakistan 10. Myanmar 11. Libya 12. Nigeria

But the MRG index found that risks rose most markedly in Yemen last year as the war raged on, with more than 10,000 people killed and millions driven from their homes.

Yemen has been torn apart by conflict since 2014, when Houthi rebels, allied with troops loyal to former President Ali Abdullah Saleh, captured large expanses of the country, including the capital, Sanaa.

A coalition of Arab countries assembled by Saudi Arabia launched an air campaign against the rebels in March 2015 to try to restore the internationally recognised government of President Abd-Rabbu Mansour Hadi to power.

"Parties on both sides of the conflict have violated international humanitarian law with impunity," the report said.

Yemen was listed eighth in a list of 70 countries where people are seen as being at risk, behind Syria, Somalia, Iraq, Sudan, Afghanistan, South Sudan and the Democratic Republic of the Congo.

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The index also said vulnerable people were at risk in a growing number of "no-go zones" around the world.

Last month, UN rights chief Zeid Ra'ad al-Hussein condemned a number of governments for refusing access to UN officials.

Mark Lattimer, MRG's executive director, said in a statement that such "international isolation is a known risk factor for genocide or mass killing".

He added that "if governments are increasingly evading international scrutiny, this is a serious concern".

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According to the report, UN human rights officials have been "granted no access to Syria since the crisis began in 2011".

In more than six years of war, at least 400,000 people have been killed, and nearly half the country's population has been displaced, according to UN estimates.

African countries top 'risers' list

Two-thirds of the countries where the risk of genocide or mass killing has risen are in Africa.

Index's top risers in 2017 1. Yemen 2. Libya 3. Nigeria 4. Burundi 5. Eritrea 6. Angola 7. Uganda 8. Turkey 9. Cameroon 10. Mozambique 11. Bangladesh 12. Papua New Guinea

According to the report, officials in Nigeria have "failed to respond to at least 14 UN outstanding requests to visit" the country.

"The government has claimed extensive military success in the war against Boko Haram, but both the Nigerian army and ... local vigilante groups supported by the government have been responsible for widespread abuses," the report said.

The report also pointed to Burundi, where protests have turned violent over President Pierre Nkurunziza's bid for a third term, Cameroon, where the government cut off internet services in the English speaking areas in 2017 after demonstrations, and Uganda where "dissent is increasingly suppressed".

MRG calculates the index based on a number of indicators, including democracy and governance, conflict data, and displacement, among others.