The United Nations Human Rights Council assembly room.  Photo: AFP

The UN voiced alarm on Tuesday at the eruption of deadly violence during protests in Eswatini, calling for an independent investigation into all alleged rights abuses, including by law enforcement.

The UN's rights office said there were claims that security forces had engaged in "disproportionate and unnecessary use of force" after being sent to quell protests that escalated last week.

Spokeswoman Liz Throssell told the reporters in Geneva there were claims police had used live ammunition, and she also highlighted reports of looting and vandalism by protesters.

"Although the situation is now reported to be calmer, we remain concerned at the potential for further unrest," she said.

The protests in the tiny landlocked southern African country, formerly known as Swaziland, first erupted in May following the death of a 25-year-old law student, allegedly at the hands of police. 

But after protesters in Africa's last absolute monarchy ramped up their campaign for political reform last week, the government deployed the army to disperse the crowds.

Unverified videos have emerged of beatings by security forces. Local civil society and opposition groups have claimed several dozens were killed. 

In New York, UN Secretary General Antonio Guterres called for both sides to address their differences "through inclusive and meaningful dialogue."

Amnesty International accused the security forces of a "frontal attack on human rights" and alleged at least 20 people had been killed.