Intensifying volcanic explosions on the Spanish island of La Palma forced firefighters to retreat and authorities to evacuate three more towns on Friday.

Airlines also cancelled flights due to a cloud of gas and ash, the biggest since the volcano erupted.

Firefighters pulled out of clean-up work in the town of Todoque on Friday afternoon as a new vent opened up in the flank of the volcano and videos shared on social media showed a massive shockwave emanating from the eruption site.

A Reuters witness saw a huge...