By Roy Ramos

ZAMBOANGA CITY, the Philippines

The Philippines military says 40 Abu Sayyaf militants have been killed and 25 wounded since army troops last week launched an offensive in the southern Philippines islands of Basilan and Sulu, two strongholds of the Daesh-affiliated group.

Major Filemon Tan, Western Mindanao Command spokesperson, said in a statement Monday that the Basilan offensive -- which began July 6 -- had left 18 militants dead and nine wounded, while the Sulu operation, which began July 7, had left 22 dead and 16 wounded.

Around 1,200 Muslim families have been affected by the heavy fighting, with houses, rubber trees and infrastructure projects laid to waste in the bombardment of Abu Sayyaf positions.

Basilan Gov. Jim Saliman said in a statement Monday that "a state of calamity" had been declared in the towns of Tipo-Tipo, Ungkaya Pukan and Albarka, which suffered from heavy shelling by troops trying to drive out militants.

A State of Calamity is used to describe “mass casualty and/or major damages to property, disruption of means of livelihoods, roads and normal way of life of people".

Ground troops continued to advance on Abu Sayyaf positions with armored vehicles while being aided by artillery fires and air strikes, said Tan.

Since 1991, the Abu Sayyaf group -- armed with mostly improvised explosive devices, mortars and automatic rifles -- has carried out bombings, kidnappings, assassinations and extortions in a self-determined fight for an independent province in the Philippines.

Earlier this year, the group beheaded two Canadian hostages after ransoms failed to be paid.