Trump's latest salvo of tariffs came into force Wednesday, hitting China the hardest and bringing levies against the world's second-largest economy to 104%.

In retaliation, Beijing hiked its own tariffs on American goods to 84%, up from an initial 34%, propelling the tit-for-tat standoff to new levels.

Beijing has called for the world to unite against Trump's aggressive trade policy, and warned that it intends to "fight it to the end".

Calling the snowballing rounds of tariffs unleashed on China since February "a grave mistake", a spokesperson for the commerce ministry said the cumulative measures highlight "the unilateral bullying nature of the US actions".

"China has initiated proceedings before the WTO's dispute settlement mechanism", he said, according to state news agency Xinhua.

Beijing "will firmly safeguard its legitimate rights and interests in accordance with the WTO rules, and resolutely uphold the multilateral trading system and the international economic and trade order," he added.

A number of countries have begun filing complaints with the World Trade Organization charging that the steep tariffs imposed by Trump violate international trade rules.

But the WTO's room for manoeuvre is limited and its dispute settlement system has been weakened over the years, including by Washington blocking the appointment of new judges.