Metro Manila (CNN Philippines, May 24) — President Rodrigo Duterte has placed Mindanao under martial law, Presidential Spokesperson Ernesto Abella said late Tuesday night.

Speaking in a joint press briefing in Moscow, Russia along with Defense Secretary Delfin Lorenzana and Foreign Affairs Secretary Alan Peter Cayetano, Abella said the President made the declaration at 10 p.m., Manila time, amid the clashes between government forces and armed Maute group members in Marawi City which erupted Tuesday afternoon.

"(Senior Deputy Executive Secretary Menardo Guevarra) has clarified that this was possible on the grounds of existence of rebellion because of what is happening in Mindanao based on Article 7, Section 18 of the Constitution. This is good for 60 days," Abella said.

For his part, Lorenzana said although the current armed conflict was only confined in Marawi City, the President decided to declare martial law all over Mindanao since there were also security problems in nearby areas like in Sulu, Zamboanga peninsula, Central Mindanao, and the Davao Region.

President Duterte said in his previous speeches that once he declares martial law in Mindanao, he would want to solve all of the security problems there, once and for all.

Lorenzana said the declaration of martial law will help the government control the terrorists' movements.

"Lahat ng gagawin na dapat gawin sa martial law (Everything that needs to be done during the martial law), we will implement. Control of movement, searches and arrest of detained people for suspension of writ of habeas corpus," he said, adding details will follow in the next days.

Maute group backed by ISIS

Lorenzana said the Maute group occupied several establishments in Marawi City: the Amai Pakpak Hospital the city hall and the city jail, as well as part of the Mindanao State University Compound.

Some facilities were also burned: the St. Mary's Church, the city jail, the Ninoy Aquino School, and the Dansalan College.

There is currently no power in the whole city.

The defense secretary said he believes the attack is backed by international terrorist group Islamic State in Iraq and Syria (ISIS).

"I believe so because we already … There have been reports that came to me from Baghdad that they are already seeing these pictures in the website of ISIS," he said, referring to the Middle East-based website of ISIS.

Lorenzana said more troops from Zamboanga and Manila will be coming in Marawi, Wednesday morning.

He also claimed the government is in full control of Marawi City.

"We will just try to hold the ground tonight so that we can bring in more troops maybe tonight and tomorrow morning. So under control 'yan," he said.

Duterte to come home

Meanwhile, Cayetano said the President has decided to cut his Russia trip short due to the incident, and fly back to the Philippines. But the new Foreign Affairs chief said agreements between the two countries would still be signed.

"The physical presence of the President is needed in the Philippines. That is the President's assessment, and his priority is always the protection of each and everyone of the Filipino, he will act within the framework of the Constitution, we will follow all rules and regulations," Cayetano said.

Duterte, who was set to meet with Russian President Vladimir Putin on Thursday, is expected to be back home Wednesday afternoon instead.

What the Constitution says

Under the 1987 Philippine Constitution, the President, as commander-in-chief, may "in case of invasion or rebellion, when the public safety requires it" suspend the privilege of the writ of habeas corpus or place the country under martial law.

The period covered should, however, not exceed 60 days. The writ safeguards individual freedom against arbitrary state action.

Other branches of government have a say in the declaration of martial law — to prevent grave abuse of discretion on the part of the chief executive.

Within 48 hours after its declaration, the President shall submit a report "in person or in writing" to Congress.

The declaration should be affirmed by Congress and should even be reviewed by the Supreme Court in an "appropriate proceeding filed by any citizen."

Congress then has the power to revoke the proclamation by a vote of at least a majority of all members of both the Senate and the House. Conversely, Congress can also — if requested by the President and if public safety requires it — extend the period of martial law beyond 60 days.

Aside from the 14-year martial law declared by late strongman Ferdinand Marcos in 1972, former President Gloria Macapagal Arroyo also declared martial law in Maguindanao on December 2009 following the Ampatuan Massacre, which killed 57 people, including media practitioners.

Davao City-based stringer Ben Tesiorna contributed to this report.

(Story updated 2:50 p.m. of May 24 to include martial law video.)