At least 50 flights were cancelled following a moderate eruption of Kanlaon Volcano on Thursday.

The Civil Aviation Authority of the Philippines (CAAP) reported two Philippine Airlines flights from Cebu going to Bacalod and vice versa were cancelled affecting over 300 passengers.

In an advisory as of 4:30 pm, Cebu Pacific also announced the cancellation of 23 flights going to and from Manila, Cebu, Legazpi, Ozamiz, Siargao, Cagayan de Oro, Davao, Clark, and Puerto Princesa.

Affected passengers have been informed via email and provided with free rebooking of their flights, travel fund and full refund of their tickets.

As of 6 pm, CAAP said a total of 54 flights were cancelled and three were diverted. PAL Express had the biggest number of cancelled flights.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said based on the seismic and infrasound records a moderate explosive eruption at the summit crater of Kanlaon Volcano occurred at 7:33 am which lasted for about three minutes.

"This event generated a dark gray eruption plume that rose 2-3 kilometers above the crater before drifting to the general east," it stated.

"Poorly visible pyroclastic density currents or PDCs descended the southeastern slopes possibly within a kilometer of the summit crater as captured by the Upper Pantao Observation Station (VKUP) in Canlaon City," it added.

However, Phivolcs noted that Kanlaon remains under Alert Level 2 and entry into the 4-kilometer-radius Permanent Danger Zone is still strictly prohibited. Robina Asido/PHS