China sharply criticized Washington's move to levy tariffs on countries trading with the Islamic Republic of Iran, issuing a statement Tuesday - less than 12 hours after President Trump announced the punitive action on Truth Social - condemning the decision.

Chinese Foreign Ministry spokesperson Mao Ning stated, "China's position on the tariff issue is very clear." She said, "We have always believed that there are no winners in a tariff war. China will resolutely safeguard its legitimate rights and interests."

The Chinse embassy in Washington also blasted the move, characterizing the US action as "exceeding legal frameworks."

The United States will impose a 25% tariff on any nation conducting business with Iran. "Effective immediately, any country doing business with the Islamic Republic of Iran will pay a Tariff of 25 percent on any and all business being done with the United States of America. This Order is final and conclusive," Trump had declared.

But this could have broader unintended consequences, and threatens to derail Washington's fragile trade deal with Beijing, which remains Tehran’s largest trading partner. According to more of the Chinese response:

The world’s top two economies had secured an interim trade deal in late October that saw a roll back of punitive U.S. tariffs on China, while Beijing paused its sweeping rare earth export controls.

In response to Trump’s tariff threat China said it “firmly opposes any illicit unilateral sanctions and long-arm jurisdiction,” while warning that it would take “all necessary measures” to defend its interests, according to a post on X by a spokesperson for the Chinese Embassy in the U.S.

Deborah Elms, head of trade policy at the Hinrich Foundation, told CNBC that if Trump is serious about the 25% rate, "that is a massive escalation from current tariff levels."

"The last time we played this game, we ended up with tariff levels at 145%" - she added, warning about the potential for a tit-for-tat spiral, which would further halt any future plans of US soybean exports to China.

Trump's tariff decision comes amid violent unrest in Iran, described by Tehran as foreign-backed riots, which have left dozens dead - or possibly even hundreds according to unverified reports - including civilians and numerous members of the security forces.

Since the unrest began more than two weeks ago, the US president has repeatedly threatened military action against Iran, pledging to "rescue" anti-government protesters. 

Iran's national currency has collapsed to a record low, effectively losing all value against the US dollar. The economic downturn, driven largely by years of brutal US sanctions, has fueled widespread public discontent. But this street anger is also being 'hijacked' by external powers which want to see Iran destabilized, weakened, and it's ruling clerics and leaders overthrown.