The US and China yesterday launched tit-for-tat tariffs on each other's imports, the opening shots in what Beijing called "the largest trade war in economic history" between the world's top two economies.

At the stroke of midnight Washington time, the US pulled the trigger on 25-percent duties on about $34 billion in Chinese machinery, electronics and high-tech equipment, including autos, computer hard drives and LEDs.

The foreign ministry in Beijing said retaliatory measures "took effect immediately" with state news agency Xinhua confirming they were also 25-percent tariffs on an equal amount of goods.

Economists have warned escalating trade frictions could throttle global growth and strike at the heart of the world trading system, causing shockwaves across the planet.

yesterday's tariffs could just be the opening skirmishes in the trade war, as

US President Donald Trump has vowed to hit as much as $450 billion in Chinese goods, the vast majority of imports.

Months of dialogue between the two economic superpowers appeared to have failed, with Trump warning just hours before the tariffs came into effect that Washington was ready to

impose duties on hundreds of billions of dollars more in Chinese imports.

Trump has for years slammed what he describes as Beijing's underhand economic treatment of the United States, with the US trade deficit in goods with China ballooning to a record $375.2 billion last year.

US officials accuse China of building its emerging industrial dominance by stealing the "crown jewels" of American technological know-how through cyber-theft, forced transfers of intellectual property and state-sponsored corporate acquisitions.

And despite dire warnings about the impact on the US, Trump believes the robust American economy can outlast its rivals in the current battle.

But China also believes that its economy, with a greater focus on domestic demand and a reduced dependence on exports, can ride out the storm.

Beijing has accused the US of" firing on the whole world" with the measures, pointing out that most of the Chinese exports under attack are largely made by companies with foreign investment - including from America.

Under the banner of his "America First" policy, Trump has also targeted other traditional trade partners of the US, such as the European Union, Japan, Mexico and even Canada.