MANILA (UPDATE) - Armed Forces Chief of Staff Gen. Rey Leonardo Guerrero on Wednesday defended the extension of martial law in Mindanao before the Supreme Court, citing how it projects authority that promotes "a climate of safety and security" in the restive region.

Guerrero made the response under the interpellation of Chief Justice Maria Lourdes Sereno during the second round of oral arguments on petitions seeking to invalidate the year-long extension of martial law.

Sereno said government officials haven't fully explained why martial law should be implemented. The chief magistrate was among 3 justices who had voted to limit martial law only to Marawi City and nearby areas when President Rodrigo Duterte's initial 60-day declaration in May was first questioned before the high court.

The Supreme Court had voted to uphold Duterte's martial law declaration in July as firefights between state troops and Islamic State-linked terrorists raged in Marawi City.

Guerrero conceded that the effect of the declaration is "partly psychological," saying it projects the image that a "strong authority is in charge."

"We need everybody to be on board for us to succeed," Guerrero told Sereno.

He added that the security threat in Mindanao is also part of a deeper societal problem.

"The problem in Mindanao, as the other parts of the country, is multidimensional. The armed conflict now is just a manifestation of a deeper problem in society," he said.

"It (martial law) enhances a climate of safety and security," he added.

'MULTI-SOLUTION APPROACH'

Guerrero also emphasized the need for a "multi-solution" approach, answering questions from Associate Justice Marvic Leonen.

“The objective is to quell the rebellion… ideally, sir, there should be no remnants,” Guerrero told Leonen.

The AFP chief admitted that the military could not reduce the threat to zero as he noted the need for a multi-solution approach to the problem.

"War today is multi-dimensional. What you see in Marawi is only one dimension to war, and that is tactical. Beneath the tactical warfare that is very obvious and very apparent are underlying elements — elements that involve politics, legal, informational, cyber, political, diplomatic, economic, and technological [aspects],” Guerrero stressed.

The military chief said martial law has “enhanced the authority” of the military in pooling together various government agencies needed to respond to the problem on the ground.

The high court on Wednesday resumed oral arguments on petitions challenging the constitutionality of the extension of martial law in Mindanao until the end of the year.

Petitioners include Albay Rep. Edcel Lagman, members of the Makabayan bloc in the House of the Representatives, former Commission on Human Rights chairperson Etta Rosales, and former Commission on Elections (Comelec) chairman Christian Monsod.

During the first round of oral arguments Tuesday, petitioners argued that the extension of martial rule is "unconstitutional," as it lacks factual basis, citing the absence of actual firefights in Mindanao.

• Mindanao martial law extension 'unconstitutional,' petitioners tell SC

Solicitor General Jose Calida, meanwhile, argued that there is sufficient basis for the extension because there is “an ongoing rebellion in Mindanao.”

• SolGen: No reason to be 'haunted' by past martial law experience

President Rodrigo Duterte had cited remaining security threats in Mindanao in seeking a second extension of martial law despite the end of hostilities in Marawi City in October.

--with a report from Ina Reformina, ABS-CBN News