MANILA - Lawmakers and human rights activists on Monday filed a separate petition before the Supreme Court questioning the extension of martial law in Mindanao until the end of the year.

Congressmen led by Albay Rep. Edcel Lagman earlier asked the high tribunal to issue a preliminary injunction and temporary restraining order (TRO) against the continuation of martial law and the suspension of the writ of habeas corpus.

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In their separate petition, groups led by the National Union of Peoples Lawyers (NUPL) also sought a TRO against the extended martial law, which they said lacks constitutional basis.

"This is a violation of the Constitution which only allows the imposition of martial law when there is actual rebellion and when the operations of the civilian government are substantially impaired that public safety should be preserved," NUPL chairman Neri Colmenares said in a statement.

"The government is functioning in Davao City and the entire country. So why replace it with martial rule?"

Colmenares said justifying martial law on the grounds of rehabilitating war-torn Marawi City or eradicating rebels are not valid grounds under the Constitution.

"Allowing these dangerously vague grounds will pave the way for President Rodrigo Duterte's imposition of martial law in the entire country since he can claim that there are rebels even in Metro Manila," he said.

The NUPL also claimed that the real target of martial law may not be lawless elements, but activists and dissenters.

Among the petitioners were Bagong Alyansang Makabayan (Bayan) chairperson Maria Carolina Araullo, BAYAN Secretary General Renato Reyes and KARAPATAN Secretary General Cristina Palabay.

Gabriela Rep. Emmi De Jesus, ACT Teachers Partylist Rep. Antonio Tinio and Kabataan Rep. Sarah Jane Elago were also named petitioners.

Congress, dominated by Duterte's allies, had approved his request to extend martial law in Mindanao to quell remaining security threats in the region that is home to 22 million.

It was the second extension of military rule, first imposed in May 2017 after firefights between the Islamic State-inspired Maute group and state troops erupted in Marawi City. The first extension was granted in July, lasting for 5 months and lapsing last December 31.

• Duterte cites terror threat, NPAs in requesting extended martial law
• Congress extends Mindanao martial law until end of 2018

The Lagman petition said there was no actual rebellion in Mindanao to justify the fresh extension.

Malacañang meanwhile said the extension would help state forces deal with lawless armed groups and ensure security during rebuilding efforts in Marawi.

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The Palace added that Duterte is seeking peace in Mindanao, not unlimited martial law.

The 5-month conflict in the southern city displaced some 350,000 residents and left dead 1,100 people.

• LOOK: How war changed Marawi City