The SUV of a ruling SKM leader in Sikkim was set ablaze at Jorethang as political violence continued unabated in the Himalayan state.

The vehicle, stuffed with SKM's party calendars, magazines and diaries, was parked near Jorethang School when it was set ablaze in the early hours of Tuesday, police said.

The SUV belonged to SKM youth convenor of Salghari-Zoom constituency John Subba, they said.

Alleging that opposition SDF was behind the incident, SKM on Wednesday said it was an attack on the people of Sikkim.

A complaint was filed over the incident and the matter is being investigated, police said.

The political situation of the otherwise peaceful state turned volatile following the return of former chief minister and SDF chief PK Chamling to the state from Delhi on December 30 after three months.

When Chamling was on the way to attend a funeral in Sadam on Sunday, Sikkim Krantikari Morcha (SKM) supporters stopped his vehicles at Melli and allegedly hurled abuses at him.

Later that day, clashes broke out between Sikkim Democratic Front (SDF) and SKM supporters at Tarey Bhir when Chamling's convoy reached the area.

SDF and SKM supporters hurled stones at each other, damaging at least four vehicles and injuring many people.

Both the parties accused the other of instigating violence in an area where many tourists were staying.

SDF accused the police of not filing a case based on its complaint, following which it met the Director-General of Police on Tuesday and sought protection for the former chief minister.

The ruling SKM also filed a complaint at the Melli police station over the incident.

Police said they are investigating the matter.