"I am warning the criminals, everybody, whether in the government or outside (of the government). I will make radical changes in the days to come," Duterte said in a news conference shortly after he arrived from Seoul for an official visit.

"There's no difference actually between martial law and a declaration of national emergency. So I've been warning all. I'm warning all including the human rights, it's either we behave or we will have a serious problem again," he added.

He said that "most of the companies (why they don't want to come) here (is the rampant crime). They are concerned by kidnappings, killings." He did not elaborate though.

"Well, somehow, even with this meager emergency power, I will use it to the hilt to put things in order," Duterte said.

In September 2016, Duterte declared an indefinite "state of national emergency on account of lawless violence" following a deadly blast in his home city of Davao that left 14 dead and dozens injured. Although the proclamation grants sweeping powers to the police and armed forces, it does not amount to martial law.

Duterte has placed Mindanao in the southern Philippines under martial rule since May 23 last year following the terror attack of pro-Islamic State (IS) militants in a bid to gain control of Marawi City. Martial law is still strictly enforced in the entire Mindanao Island until the end of December this year.