Eswatini police have fired teargas and water cannon at anti-monarchy protesters, the head of a teachers' union says, while videos on social media showed demonstrators running away as shots rang out in the background.
Campaigners organised the latest round of demonstrations after the authorities quashed days of violent protests at the end of June against King Mswati III, Africa's last absolute monarch.
In his first remarks on the protests, the king called them "satanic" and said they had taken the country formerly known as Swaziland backwards.
The king denies critics' accusations of autocratic rule and of using public money in an impoverished country to fund a lavish lifestyle spread across several palaces housing him and his 15 wives.
Police fired teargas and used water cannon to disperse protesters in Manzini, Eswatini's second largest city, Swaziland National Association of Teachers (SNAT) Secretary General Sikelela Dlamini told Reuters.
A video posted to Facebook by the Swaziland Democratic Front, a pro-democracy coalition including political parties, churches and unions, showed protesters singing and dancing in the street before fleeing as shots rang out behind them.
It was not clear who was firing or what they were shooting at.
The king made his remarks on the protests during a public meeting known as a Sibaya.
"The country views that conduct as satanic," he said, announcing a 500 million swazi lilangenis ($A46.92 million) fund to help repair damage worth 3 billion lilangenis.
Citizens across the country are invited to the Sibaya, usually held once a year and a time-honoured way for them to express grievances before the king.
Friday's was seen as a test of his popularity following the protests in late June.
Those attending cheered his remarks from the grass in a cattle byre at one of his residences.
Pro-democracy campaigners organised their latest anti-monarchy rally to coincide with the Sibaya.
Protesters who took to the streets were met with resistance from authorities.
National Police Commissioner William Dlamini told the state broadcaster police would use maximum force if needed.
During the previous round of protests, some demonstrations descended into rioting and looting.
Mswati also on Friday appointed Cleops Dlamini, the former head of the Public Service Pension Fund, as the country's new prime minister following the death of his predecessor Ambrose Mandvulo Dlamini in December.
Australian Associated Press