MANILA: The Philippine government slammed China on Monday for "repeated aggressive, unprofessional and illegal" actions in the South China Sea after a string of clashes and incidents on air and at sea over the past week.

The Philippines' national maritime council said Chinese aircraft made unsafe manoeuvres against a civilian aircraft conducting patrols over the Scarborough shoal and Subi reef.

On Sunday, Chinese vessels also "blocked, rammed and fired water cannons" against a government fisheries vessel while doing a resupply mission to Filipino fishermen in Sabina shoal, it said.

These actions are "alarming", the maritime council said in a statement.

" calls into question China's supposed commitment to de-escalate the situation in the area and create a conducive environment for dialogue and consultation," the council said.

The Philippines added it will continue to pursue diplomacy in managing the maritime issues, and urged China "to return to the path of constructive dialogue" on South China Sea matters.

Philippine Defence Minister Gilberto Teodoro separately said on Monday that China's actions were "patently illegal" following the clash near Sabina shoal.

"We have to expect these kinds of behaviour from China because this is a struggle. We have to be ready to anticipate and to get used to these kinds of acts of China which are patently illegal as we have repeatedly said," Teodoro told reporters.

In the incident at Sabina shoal, Manila's South China Sea task force accused Chinese vessels of ramming and using water canons against a Philippine fisheries vessel transporting food, fuel and medicine for Filipino fishermen.

The Chinese coast guard said the Philippine vessel "ignored repeated serious warnings and deliberately approached and rammed" China's law enforcement boat, resulting in a collision.

Asked if the latest incident would trigger treaty obligations between the United States and the Philippines, Teodoro said: "That is putting the cart before the horse. Let us deter an armed attack, that is the more important thing."

The Philippines and the United States have a mutual defence treaty and Washington has vowed to aid the Philippines against armed attacks on its vessels and soldiers in the South China Sea.

The Chinese embassy in Manila did not immediately respond to a request for comment. Monday is a public holiday in the Philippines.

China claims sovereignty over nearly all of the South China Sea, including areas claimed by the Philippines, Taiwan, Malaysia, Indonesia, Vietnam and Brunei.

An international arbitral tribunal in 2016 ruled that China's claim had no basis under international law, a decision Beijing has rejected.

 - Reuters