China on Tuesday voiced "firm opposition" to the Philippines' decision to draw a third party into the incident over Huangyan Island.

The move will "further escalate the situation and even change the nature of the issue," Foreign Ministry spokesman Hong Lei said during a routine press briefing.

A recent Philippine media report quoted the country's foreign affairs secretary as saying that some countries are helping the Philippines to establish a "minimum credible defense posture" to complement its diplomatic capacity in dealing with territorial disputes with China.

When asked to comment on the report, Hong said China has consistently used diplomatic means to urge the Philippines to correct its mistakes and ease the situation.

Hong reaffirmed that Huangyan Island is an inherent part of China's territory.