US equity indexes were off session lows in choppy midday trading Monday as investors tackled trade tariff rumors amid President Donald Trump's threats of more punitive import duties on China.

The Nasdaq fell 0.1% to 15,562.4 after touching an intraday low of 14,784.03. The S&P 500 dropped 0.5% to 5,049.2, following a decline to 4,835.04 earlier in the session. Similarly, the Dow Jones Industrial Average traded 1.2% lower to 37,836.4 after touching a low of 36,611.78 in the morning session. All three indexes touched their respective 52-week low intraday.

All sectors, except communication services and technology, declined in midday trading, with real estate and utilities as the steepest decliners.

The CBOE Volatility Index jumped 7.7% to 48.78 intraday, the second-highest to the all-time high seen in January 2020, with data compiled by CNBC going back to the 1990s. The current level of volatility is above the peak that the index scaled during the global financial crisis.

Almost all US Treasury yields rose intraday, with the 10-year yield up 20 basis points to 4.19% and the two-year rate 9.7 basis points higher at 3.77%.

President Donald Trump said Monday that he plans to impose an additional 50% tariff on China if the world's second-largest economy fails to withdraw the retaliatory tariff it had announced last week on the US. "Additionally, all talks with China concerning their requested meetings with us will be terminated!" he wrote in a message on Truth Social.

The White House, meanwhile, told CNBC that any talk of a 90-day pause in implementing tariffs on all countries except China was "fake news."

"We had expected the White House to announce a more aggressive 'reciprocal' tariff at first and then scale it back somewhat," Goldman Sachs said in a note. "If most of the 'reciprocal' tariff goes into place on April 9, we expect to change our forecast to a recession."

Investors ought to consider various scenarios in the days ahead, Deutsche Bank said in a note. The main point to deliberate is whether the administration tries to find an off-ramp from the tariffs, potentially moving to negotiations, or double down. "This is crucial as it will impact not just trade, but the whole geopolitical relationship between the US and the rest of the world."

In company news, AppLovin (APP) Chief Executive Officer Adam Foroughi told MT Newswires that the company's offer for TikTok can "provide a win for the Trump administration and for the creators of TikTok." Shares jumped over 8% as trading volume rose over 10 million against a daily average of about 8.44 million.

West Texas Intermediate crude oil futures dropped 1.4% to $61.13 a barrel.

Gold futures slumped 1.6% to $2,985.02 per ounce. Silver futures jumped 1.8% to $29.75 per ounce.