MANILA — Philippine troops have killed 40 Abu Sayyaf extremists and wounded 25 others in two battlefronts in the first major counterterrorism offensive in the south under the new president, the military said Monday.

Regional military spokesman Major Filemon Tan said 22 militants had been killed and 16 others wounded in the assaults that started last week in the jungles of Sulu, a predominantly Muslim province where the ransom-seeking militants are also believed to be holding a number of foreign hostages.

One soldier had been killed in the fighting in impoverished Sulu, about 590 miles south of Manila, he said.

On the nearby island province of Basilan, 18 Abu Sayyaf fighters had been killed and nine others wounded in a simultaneous offensive centering in the town of Tipo Tipo, according to Tan.

President Rodrigo Duterte, who started his six-year term on June 30, has warned the Abu Sayyaf to stop a wave of ransom kidnappings.