The S&P 500 sold off sharply on Tuesday to close below 5,000 points for the first time in almost a year after it reversed a strong morning rally, while investor hopes faded for any imminent U.S. delays or concessions on tariffs ahead of a midnight deadline.

Policymakers across Asia are preparing measures to support financial markets as a rout deepened following sweeping tariffs announced by U.S. President Donald Trump that stoked widespread recession worries.

Beijing accuses the US of "blackmail" after Trump threatens to impose more duties if China does not retract its counter-tariff plans by Tuesday.

Asian shares are mostly falling, shaken by jitters over what President Donald Trump will announce about tariffs on his “Liberation Day” later in the global day

Stock markets posted big losses on Monday as investors fear a global trade war. President Donald Trump has given no sign of backing down on tariffs.

Japan's benchmark Nikkei 225 plunged nearly 4 per cent at the opening bell, before recovering slightly to trade 3.5 per cent lower at 31,847.40. South Korea’s Kospi index fell 1 per cent to 2,315.27, while Australia’s S&P/ASX 200 declined 2 per cent to 7,359.30. Markets in New Zealand also registered losses.

The Indian rupee logged its steepest one-day decline in nearly three months on Monday as concerns over U.S. President Donald Trump's sweeping tariff plans jolted global financial markets, dragging Asian currencies and stocks lower.

The trading curbs go into effect when the S&P 500 crosses certain thresholds during extreme market volatility.

Mr Trump's bombshell tariff announcement causes more turmoil as investor fear grows over a global trade war and a possible recession in the US.

Overnight, US markets tumbled with NASDAQ Composite Index slipping 1050.44 pts or 5.97% to 16,550 and S&P 500 index ending 274 points lower at 5,396.

Asian grocery stores are a lifeline to the communities they serve. But store owners say the prospect of sweeping tariffs are threatening their ability to stock up on goods and keep prices affordable.

Asian shares nosedived on Monday after the meltdown Friday on Wall Street over U.S. President Donald Trump's tariff hikes and the backlash from Beijing. U.S. futures also signaled further weakness. The future for the S&P 500 lost 2.