MANILA (UPDATE) – President Rodrigo Duterte met with members of left-wing Bagong Alyansang Makabayan (Bayan) Tuesday night and had "serious" discussions on urgent issues, including his martial law declaration in Mindanao.

Present at the meeting in Malacañang were key leaders of the Left, among them Bayan secretary-general Renato Reyes Jr., Bayan Muna party-list Rep. Carlos Isagani Zarate, former Bayan Muna Rep. Neri Colmenares and National Anti-Poverty Commission Secretary Liza Maza.

The talks happened just hours after the President sought to extend until the end of 2017 the implementation of martial law in Mindanao, which militants have been opposing since it was first laid down on May 23.

It was set on the same night that Duterte ordered the government panel to halt peace talks with the left until communist rebels stop attacks on state forces.

Reyes said unlike previous meetings, Tuesday’s discussions were “more serious” as it “revealed glaring differences on major issues.”

In a statement, Reyes said the President seemed “bent on extending” the martial law proclamation in Mindanao despite their strong opposition.

Members of leftist organizations are opposing Duterte’s request for Congress to extend his martial law proclamation in Mindanao until Dec. 31, 2017, saying military rule has resulted in numerous human rights violations.

• READ: Duterte calls for special session on martial law extension

The President's 60-day declaration is set to lapse July 22. Congress is set to hold a joint session on Saturday to vote on Duterte's request.

“[The President] said that it was not intended to target the Left. The Mindanao activists said that that was not the reality on the ground,” Reyes said.

“They related how martial law is being used to militarize communities and attack Lumad schools. Several communities have been displaced as a result. Lumad leaders showed the President pictures and other documentation,” he added.

Reyes said Duterte made no commitment on the Left's demand for the military to leave communities.

“[The President said] this was a reality in the ongoing civil war. For our part, a condition of extended martial law can only mean that military abuses and attacks will increase,” he said.

Duterte’s chief legal counsel, Salvador Panelo, however disputes claims of human rights violations under the Mindanao martial law.

"As to the fear of military abuses in the event of an extended martial law, the same is misplaced. There have been no reported cases of abuses committed by the military and the police in the almost two months of martial law in Mindanao," Panelo said in a statement.

"[The President] is against any kind of abuse of power by the men in uniform. There will be hell to pay for those who commit atrocities in the course of implementing martial law as they will not go unpunished," he said.

In opposing Duterte's planned martial law extension, the Communist Party of the Philippines asked the New People’s Army to “strengthen itself nationwide by carrying out armed counteractions and offensives across the country to defeat the Mindanao martial law and nationwide all-out war.”

In response, Presidential Spokesperson Ernesto Abella asked the CPP to “reciprocate the government’ gestures of goodwill by ending their extortion and criminal activities and re-directing their energy to help eradicate terrorism and violent extremism in Mindanao.”

On Monday evening, Duterte sent to Congress a 7-page letter with a detailed report justifying the need to extend martial law.

Abella earlier said Duterte asked for the martial law extension to allow government troops to deal with the Marawi crisis “unhampered by deadlines” and focus on rebuilding the city.

Senate President Aquilino Pimentel III and Speaker Pantaleon Alvarez said Congress, dominated by the President’s allies, is likely to approve the request for martial law extension, even as some opposition lawmakers believe the extension should not be beyond 60 days.

• READ: Extending Mindanao martial law until December illegal: Lagman

Duterte placed the entire Mindanao under martial law on May 23 after the Islamic State-linked Maute and Abu Sayyaf groups laid siege on Marawi City in a bid to establish an ISIS province in the Philippines.

The long-drawn conflict in Marawi, considered one of the most important Islamic cities in the predominantly Catholic Philippines, has left at least 556 dead, most of them terrorists.

The emergence of groups pledging allegiance to Islamic State has been considered the biggest security problem to face the year-old Duterte administration.

The rise of pro-ISIS groups in the country has also raised alarm in Washington and the Philippines’ neighbors in the region, which fear that the notorious terror group was seeking to establish a new front in Asia amid its successive losses in Iraq and Syria.