Phillipine President Rodrigo Duterte said Monday he could not stop Chinese men from fishing his country's exclusive economic zone in the disputed South China Sea.

In his annual state of the nation address, Duterte told congress the Phillipines would certainly lose in any clash over his country's exclusive economic zone, which is claimed by China.

"When Xi (Jinping, Chinese President) says I will fish, who can prevent him?" Duterte asked as he defended his non-confrontational approach to China over the territorial disputes.

"If I send my marines to drive away the Chinese fishermen, I guarantee you not one of them will come home alive," Duterte said, adding that diplomatic talks with Beijing have allowed the return of Filipinos to disputed fishing grounds where Chinese forces previously shooed them away.  

Critics have repeatedly criticised Duterte, who has nurtured friendly ties with Beijing, for not standing up to China's aggressive behaviour in the disputed waters and for deciding not to immediately seek Chinese compliance with an international arbitration ruling that invalidated Beijing historic claims to virtually the entire sea.

"Do you want war?" he asked.

The Philippines' long-simmering territorial rifts with China and Duterte's centerpiece campaign against illegal drugs and corruption were spotlighted in his speech.

The 74-year-old took office in June 2016 and has remained hugely popular in opinion polling despite drug war deaths that have sparked international alarm and other controversial policies.

More of his allies captured congressional seats in midterm elections in May, giving them a tighter grip on the legislature, especially in the 24-member Senate, which opposed some of his key legislative proposals last year, including reinstating the death penalty and amending the pro-democracy constitution.

More than 5,200 protesters rallied despite a downpour outside the House complex to call for Duterte's removal while a smaller number of pro-Duterte supporters rallied separately.

Protest leader Renato Reyes Jr said protesters were fighting to have Duterte's term cut short, adding "the killings are not stopping and he's going to go for more."

Left-wing protesters burned a mock Chinese flag and a giant mural with the images of Duterte, Xi and US President Donald Trump.

Military and police were placed on full alert and authorities declared a no-fly zone over the venue and outlying areas to ensure security.

Manila - 22 July 2019

1. Wide of Philippine Congress hall applauding President Rodrigo Duterte

2. Mid of Congressmen applauding

3. Duterte walking to podium

4. Wide of hall

5. SOUNDBITE: (English/Tagalog) Rodrigo Duterte, Phillipine President:

"I cannot go there (South China Sea) even to bring the coastguard to drive them (Chinese) away. China also claims the property and he is in possession, that is the problem."

6. Cutaway of congressmen watching Duterte's speech

7. SOUNDBITE: (English/Tagalog) Rodrigo Duterte, Philippine President:

"If I send our Marines to drive away the Chinese fishermen I guarantee you not one of them will come home alive."

8. Cutaway of congressmen watching Duterte's speech

9. SOUNDBITE: (English/Tagalog) Rodrigo Duterte, Philippine President:

"When Xi (Jinping, Chinese President) says I will fish who can prevent him? I also said we will fish because we claim it, I said please allow because before that they were driving away our fishermen. I said do not drive them away because the Filipinos are of the belief that they also claim it."

10. Wide of Duterte at podium, congressmen applauding

11. SOUNDBITE: (English/Tagalog) Rodrigo Duterte, Philippine President:

"Of course there are already guided missiles in that island and the fastest that they have installed there can reach Manila in seven minutes. Do you want war?"

12. Various of protest march

13. Protesters marching while holding banner reading (English): "No to PH-China deals!

14. Protest banner reading (English): "Oust Duterte"

15. Pan from protest banner that reads (English): "Stop the killings!" to effigy depicting Duterte as a seamonster

16. Various of burning effigy depicting Duterte as a sea monster holding up a gun and a mock China flag

17. SOUNDBITE (English) Renato Reyes Jr, protest leader:

"So it's going to be a real fight for the next three years and people are thinking maybe it would be better if his (Duterte) term is cut short. Considering that the killings are not stopping and that he's going to go for more." ++NIGHT SHOT++

18. Wide of protesters