Guides who take tourists to see Mount Etna in Sicily said they are protesting tougher restrictions imposed by local authorities as the volcano continues erupting and has been showing lava flows for weeks.

Authorities in the city of Catania suspended or restricted excursions to see the lava, prompting guides to go on strike for the first time in decades. On Wednesday, dozens of the guides demonstrated in front of a lava flow gate, with fewer options for tourists to view the eruption close up.

The guides said the limits are excessive. “These measures effectively nullify the role of guides, stripping them of their skills, function, and professional responsibility,” a statement by the guides’ regional board said.

Under the new rules, excursions are allowed only until dusk and can go no closer than 200 meters (660 feet) to the lava flow. The restrictions also enforce a previously existing limit of 10 people per group, including with drones, according to the AP report.

Mount Etna is Europe’s most active volcano and the continent’s largest, drawing hikers and backpackers to its slopes and less adventurous visitors to viewpoints from a distance. AP reported that the latest restrictions were adopted after Mount Etna began a round of eruptions on Christmas Eve.

Local authorities said the most advanced lava front reached 1,360 meters above sea level before stopping and entering a cooling phase after traveling about 3.4 kilometers. They said the lava flow poses no danger to nearby residential areas, and volcanologists also gave the same assessment.

Italy’s National Institute of Geophysics and Volcanology confirmed that the eruption is ongoing but said the lava fronts are cooling and not advancing further, AP said.

Guides argued that conditions are calm enough for safe viewing. Dario Teri, 43, a member of Sicily’s association of alpine and volcano guides who took part in Wednesday’s protest, said: “This is a lava flow that is descending very slowly on an area that is now also flat or semi-flat,” AP reported.

The guides said they expected to continue their strike in the coming days and were seeking a compromise with authorities that could protect their profession while ensuring visitor safety. Claudia Mancini, a 32-year-old tourist from Palermo, said she had traveled for an excursion with a guide but received news that “all activity” had been canceled. She added that she sympathized with the guides and said the situation “is not making anyone happy.”