The tallest active volcano in Europe, Etna has been spewing ash and lava for days, forcing the closure of the nearby Catania airport, a key gateway for tourists visiting the island of Sicily.Companies that organise nighttime hikes allowing participants to watch the eruption up close say they have been flooded with calls."They all want to come and see the lava flow, everyone is drawn to this unique beauty," Daniele Perricelli, 41, a local guide told AFP on Wednesday. Perricelli's group, Guide Etna, takes a few dozen visitors up the volcano every evening -- but is currently receiving about 300 requests a day, three times what it gets on an average summer day, he said.

Ash emissions have caused Catania airport to repeatedly halt flights over the past few days © Handout / Etna Walk/AFP

Ernesto Maria Magri, another local guide, called it a "touristic eruption" that appeals to "many people" because it can be observed in relative safety.Even though the volcano erupts frequently, he said many local residents were also climbing up to see the lava and "sometimes crowd round in a disorderly way". Unwilling or unable to secure a guide, many venture up on their own. That is potentially risky, said Perricelli, explaining the volcano was unstable and it was important to be with someone who could read the mountain.Safety concerns"There are up to 2,000 people climbing up every evening, the footpaths are overcrowded," he said. "Yesterday, we saw some wearing flip-flops," he added, calling on authorities to be more vigilant. Some climbers, including Italian TV host Diletta Leotta, have been criticised on social media for taking photos seemingly too close to glowing lava.