Watch more in iWantv or TFC.tv

COTABATO CITY -- (4th UPDATE) At least 2 people died while 34 others were injured in a blast at a department store here, as shoppers were busy preparing for new year revelries, authorities said Monday.

Maj. Gen. Cirilito Sobejana, commander of the Philippine Army's 6th Infantry Division, said several minors were among the wounded in the explosion that occurred at about 1:49 p.m.

"We're actually providing security (in the area) but we missed a spot because of the high number of people around," Sobejana said.

Of the 34 injured, at least 10 are still recuperating in the hospital, the police said Tuesday.

Market-goers scampered for safety after an explosion hit the entrance of South Seas Complex at Don Rufino Alonzo St., which has since been declared under "lockdown," police said.

Sobejana said witnesses saw an individual put a box in front of a firecracker stall. The bomb exploded there just seconds after, he added.

Cotabato police said an improvised explosive devise was found at the department store where the blast occurred. The military said this could be an attack by terrorist group Daulah Islamiyah.

"The IED that exploded earlier carries the signature of a Daesh-related group," Sobejana told ANC in an interview Monday evening.

Sobejana said soldiers killed 7 members of the group in a focused military operation in Maguindanao on Thursday, December 27, and this incident could be a form of retaliation. Authorities continued to probe the incident.

The blast happened despite martial law being in effect in Mindanao. Sobejana said state troops are trying their best to prevent terrorist activities in the country's south.

"Two days ago, I sent a radio message to unit commanders under my command to increase their level of vigilance because there are a lot of threats around," he said.

"It's really hard for us to secure all the quarters of our areas of responsibilities," the military official added, reminding the public to be vigilant.

Meanwhile, Malacañang asked the public to avoid speculations related to the incident.

"We are extremely saddened by the explosion that took place in Cotabato City yesterday. Authorities are already investigating the incident. In the meantime, we call on everyone not to speculate as this may only sow unnecessary fear and panic among our people," Presidential Spokesperson Salvador Panelo said in a statement Tuesday.

"We empathize with the families, relatives and friends of those who suffered from this unhappy occurrence. To them we vow that we will get to the bottom of this at the soonest possible time," he added.

Watch more in iWantv or TFC.tv

BASAHIN: Pahayag ni Presidential Spokesperson Salvador Panelo sa nangyaring pagsabog sa Cotabato City | via @joycebalancio pic.twitter.com/fMr7iolvCf

— ABS-CBN News (@ABSCBNNews) January 1, 2019

— with reports from Lore Mae Andong and Arianne Apatan, ABS-CBN News