President Rodrigo Duterte would ask Congress to extend martial law in the whole of Mindanao until end of the year.

In a press briefing on Tuesday, Presidential Spokesperson Ernesto Abella said Duterte, in his letter to the leadership of the Senate and the House of Representatives, has asked Congress to extend martial law until December 31, 2017 to fully quell rebellion in Marawi City and other parts of Mindanao.

Duterte would request for about five-month extension following a "thorough personal assessment of the current situation in Marawi City and other parts of Mindanao," Abella said.

He said the president also took into account the reports and recommendations of Defense Secretary Delfin Lorenzana, as martial law administrator, Armed Forces of the Philippines chief of staff General Eduardo Ano, as martial law implementor, and Philippine National Police chief Director General Ronald dela Rosa.

"(I) have come to the conclusion that the existing rebellion in Mindanao which has prompted me to issue Proclamation No. 216 from 23rd May 2017 will not be quelled completely by 22nd July 2017, the last day of the 60-day period provided under Section 18, Article VII of the 1987 Constitution," Abella read Duterte's letter addressed to Senate President Aquilino Pimentel III and House Speaker Pantaleon Alvarez.

"For this reason then because public safety requires it, I call upon the Congress to extend until 31st of December 2017 or for such a period of time as Congress may determine the proclamation of martial law and the suspension of the privilege of the writ of habeas corpus in the whole of Mindanao," the President said.

"The primary objective of the possible extension is to allow our forces to continue with their operation unhampered by deadlines and to focus more on the liberation of Marawi and its rehabilitation and rebuilding," Duterte added.

Duterte, who hosted a dinner with some senators and congressmen in Malacanang on Monday, has requested Congress to hold a special session on Saturday to discuss his request for the extension of martial law.

Abella said the president may or may not join in the special session.

Duterte declared martial law in Mindanao on May 23 shortly after the Islamic State-inspired Maute Terror Group attacked and occupied Marawi. Celerina Monte/DMS