About 100 heavily-armed members of the communist New People's Army (NPA) posing as soldiers wounded five members of the Presidential Security Group (PSG) in an ambush in North Cotabato province in restive Mindanao.
"The conditions (for their conditional release) provide that should the formal peace negotiations cease or fail, their bond shall be deemed automatically canceled", it added.
Meanwhile, Armed Forced of the Philippines (AFP) public affairs chief Col. Edgard Arevalo said the President's chopper landed even as troops were launching a daring assault from the other end of Mapandi Bridge - site of one of the fiercest gun battle in downtown Marawi.
Duterte was not with the PSG convoy.
"The president directed the government panel. not to resume formal peace talks unless the reds (rebels) agree to stop their attacks against government troops in Mindanao", said a statement issued by the presidential palace.
However, Dureza later on announced the government will not hold informal talks with the communist rebels following the PSG encounter with the insurgents.
Clad in military fatigues, Duterte set foot on the city's military detachment past 2 p.m. (0600GMT) along with defense chief Delfin Lorenzana, National Security Adviser Hermogenes Esperon, and military chief Eduardo Año, local media reported.
The fifth round of peace talks with the rebels was suspended on May 27 following orders by the CPP to the NPA to intensify attacks against security forces after Duterte declared martial law in Mindanao on May 23.
On Tuesday he asked Congress to extend a state of emergency in the south until the end of the year.
The Communist Party of the Philippines had responded to the extension Tuesday, accusing Duterte of laying the foundations for dictatorship and assaulting the rights of Filipinos "under US imperialist tutelage".