ZAMBOANGA CITY: Two people were killed and two others wounded following a bomb explosion on Thursday outside a hotel in Cagayan de Oro City. It was the second bombing in a span of two days in the southern Philippines, authorities said.

It said that the bomb was left near the Maxandrea Hotel in downtown Cagayan de Oro, but the motive of the explosion is still unknown. Among the wounded were policemen who were in the area to investigate the explosive.

No individual claimed responsibility for the blast, but police said that the improvised explosive device contained iron nails.

The latest explosion came a day after authorities arrested two men who exploded a grenade under a truck driven by a hotel owner in Zamboanga City.

Officials said that a boy, who was near the explosion, was hit by shrapnel and injured as policemen gave chase on the men who tried to escape on a motorcycle after the daring attack at an intersection just outside a military base.

Two other accomplices from the village of Mampang, believed to be hired killers, were also arrested following a subsequent police operation. The assailants lobbed two grenades, but only one had exploded under the truck, damaging two of its huge tires, officials said.

“Only one grenade exploded and we recovered the other one. No one among the four passengers were injured in the blast, but a boy who was watching cars, was injured and rushed to hospital,” a member of the police bomb squad told the The Manila Times.

He said that the passengers of the truck, including the owner of the Blue Shark Hotel, were uninjured from the attack, although shaken from the explosion.

The motive of the attack is also unknown and there appears no links to the Cagayan de Oro blast, but police has started its investigation to determine who ordered the failed assassination.

“There is an investigation going on and the arrest of the assailants will surely shed light as to the motive of the attack,” Army Colonel Buenaventura Pascual, commander of the anti-terrorist Task Force Zamboanga, said.

The attack occurred just as Zam-boanga is celebrating its feast of the Virgin Mary.

Gun attacks and killings are not uncommon and almost a daily occurrence in Zamboanga City. In one of the attacks, the president of a university was shot dead by motorcycle gunmen near his house.

Since January this year, there were over 100 killings so far and most of them are perpetrated by guns-for-hire who are actively operating in Zamboanga.