President Rodrigo Duterte has decided not to commemorate the start of the five-month Marawi siege, which took place a year ago.

In a text message to reporters on Wednesday, Presidential Assistant to the President Christopher "Bong" Go said Duterte had no plan to go to Marawi.

"No sked (schedule) siege (commemoration)," he said.

If Duterte would lead any commemoration, he said it would be the liberation of the city from the hands of the Islamic State-inspired Maute terrorists.

"We will go to Marawi during its liberation. Not the start of the siege. Why honor (it)?," Go added.

Maute-ISIS terrorists attacked and occupied Marawi starting May 23 last year. During that time, Duterte was on his trip to Russia.

The President had to cut short his trip and while in Moscow, he declared martial law in the whole of Mindanao.

In a speech during the 120th Philippine Navy anniversary on Tuesday, Duterte recalled that the Marawi siege was a "very sad experience."

"And we all know and - that we have fallen short in some respect the way it was handled. I assume full responsibility," he said.

The President admitted that the government did not anticipate that much ordnance had been stored by the terrorists in the city.

Duterte declared Marawi's liberation in October last year after the death of most of Maute-ISIS leaders led by Isnilon Hapilon and the Maute brothers.

Hundreds of people, including government troops, civilians and terrorists, died, while hundreds of thousands of residents were displaced during the siege.

The government has yet to commence the full rehabilitation of the city, particularly the most affected areas. Celerina Monte/DMS