* Some protesters had shotgun wounds, broken bones - UN
* PM refuses to resign, says opposition stirring trouble
GENEVA Nov 30 (Reuters) - The top United Nations human rights official accused Tunisia's security forces on Friday of using excessive force to quell a protest in an economically deprived region of the north African country.
Navi Pillay, High Commissioner for Human Rights, said the authorities must stop using firearms against demonstrators in some of her harshest criticism of the Islamist-led government brought to power by an Arab Spring uprising last year.
The tactics used to put down the protests this week have stirred anger among secular politicians in Tunisia, who say the new government is advocating the kind of harsh policing long employed by ousted autocrat Zine al-Abidine Ben Ali.
More than 220 people are believed to have been injured when the demonstrators demanding jobs clashed with police on Tuesday and Wednesday in Siliana, a city on the edge of the Sahara whose inhabitants have long complained of neglect.
Staff from Pillay's office visited protesters admitted to hospital in the capital Tunis with shotgun wounds to the head, back and face, her spokesman Rupert Colville said.
Some had eye injuries that could lead to blindness, while others had broken bones.
"The High Commissioner condemns the excessive and disproportionate use of force by members of the security forces against the protesters, whose demonstration was announced in advance," Colville told a news briefing in Geneva.
"In particular, she is urging the authorities to immediately halt the use of shotguns against protesters," he said, while adding that protesters should also avoid resorting to violence.
A team of U.N. rights officials arrived in Siliana on Friday for talks with local authorities and Pillay's staff also planned to visit police officers injured in the unrest, Colville said.
Up to 10,000 people protested again in Siliana on Friday, demanding the removal of the local Ennahda governor, a witness and local activist said.
"Police have fired teargas on protesters and are chasing people down the streets, but it's much more calm than previous days," said a resident who gave his name as Amin. "They are shouting for the end of Jebali and the governor. They have the slogan: Jebali 'Game over'"
"Game over" was a slogan used in the 2011 Tunisian uprising that was taken up by protesters in other Arab countries.
Prime Minister Hamadi Jebali, from the Islamist Ennahda party that rules with two junior leftist partners, rejected calls for his resignation on Thursday and accused opposition parties of sowing disorder.
"The rights to freedom of expression and opinion, and peaceful assembly, are fundamental human rights which must be protected and respected," said Colville. (Reporting by Stephanie Nebehay)