Japan's Nikkei index fell 3.93 per cent to close at 31,714.03, while the broader Topix index settled 3.40 per cent lower at 2,349.33. Tech stocks suffered heavy losses, with SoftBank Group, Advantest, and Tokyo Electron plummeting six to eight per cent.
MSCI's broadest index of Asia-Pacific shares outside Japan dropped 1.9 per cent.
Conversely Chinese markets reversed early losses and gained ground after Beijing published a white paper indicating openness to talks following the US tariffs.
The blue-chip CSI300 Index opened down but then clawed back losses to end one per cent higher, while the Shanghai Composite Index rose 1.3 per cent. Hong Kong's benchmark Hang Seng rose 0.7 per cent.
China on Wednesday said it would take resolute and effective measures to safeguard its rights and interests in response to Trump's duties on Chinese imports.
China also released a White Paper said Beijing was willing to communicate with Washington to resolve differences and friction that it considered normal for the world's two biggest economies.
"Risk assets have bounced on a white paper that suggests China is open to dialogue - though does not confirm US/China negotiations are under way and means further headline noise is inevitable," Citi analysts said in a note.
Reuters reported China's top leaders plan to convene a meeting as early as Wednesday to discuss measures to boost the economy and stabilise capital markets.
"The first real battleground of the tariff war is financial markets, especially stock markets," said Ting Lu, chief China economist at Nomura. "The financial markets of both economies have been severely hit, and the worst might be yet to come."
Lu expects China's stabilisation funds, supported by the country's central bank, to intervene significantly in stock markets over coming weeks.
China's biggest brokerages have pledged to help steady domestic share prices, the Shanghai bourse said, while scores of listed companies said they planned to buy stocks.
Chinese state holding companies, led by Central Huijin, continued to support the stock market by increasing share investment.
Mainland investors bought Hong Kong shares worth a net $HK35.5 billion ($A7.42 billion) via the Stock Connect scheme on Wednesday, the highest on record.
The escalating trade war has also prompted investors to shift their attention to self-reliant high-tech sectors, seen as winners in China's push for technological independence. Semiconductor and AI-related shares rose 5.3 per cent and 3.4 per cent, respectively.
Chip giant SMIC listed in Hong Kong surged around 10 per cent.
In Europe, the STOXX 600 fell nearly three per cent in early trading, bringing the loss in market capitalisation since April 1 - the day before Trump unveiled his tariffs - to around $US1.4 trillion.
US stock futures were anchored in negative territory, down 0.3 per cent on the day .
Analysts at JPMorgan believed the rapid escalation with US tariffs on China were disruptive enough to push the global economy into recession.
"Given the import bill from China, the China tariff alone amounts to a whopping $US400 billion tax hike on US households and businesses," they said in a note to clients. "The currency is likely to be a release valve for China policymakers."
Safe-haven currencies like the yen and Swiss franc found some more love, with the dollar skidding 0.9 per cent to 145 yen and down 0.5 per cent to 0.843 Swiss franc.
Oil prices fell as much as four per cent as concern over the outlook for global energy demand outweighed any nervousness on the geopolitical front. Brent crude futures were last down 2.4 per cent at $US61.30 a barrel.
Gold regained its upward momentum and was last up two per cent at $US3,005 per ounce.
with DPA
