Philippines National Security Council spokesperson Jonathan Malaya said on Tuesday that Manila has lodged a protest over the presence of the 165-metre (541ft) long Chinese coastguard vessel 5901, which was spotted 77 nautical miles (142km) off the coast of Zambales province, and demanded its withdrawal from the EEZ.

“We were surprised about the increasing aggression being showed by the People’s Republic of China in deploying the monster ship,” Malaya said.

“It is an escalation and provocative,” he said, saying the presence of the vessel was “illegal” and “unacceptable”.

The Philippine Coastguard said it had deployed two of its largest vessels to drive away the Chinese vessel.

Chinese Ministry of Foreign Affairs spokesperson Guo Jiakun said on Monday that its coastguard’s’s “patrol and law enforcement activities” were “reasonable, lawful and beyond reproach” in the area.