China, Hong Kong stocks weaken to near one-month low on tariff concerns

China and Hong Kong stocks fell on Monday, joining a broader equity rout in the region as concerns heightened ahead of US President Donald Trump's tariff policy announcement scheduled for Apr 2.

At the midday break, both China's blue-chip CSI300 index and the Shanghai Composite index slipped 1 percent to their lowest in nearly one month.

The consumer staples sector lost 1.3 percent and the artificial intelligence index down 1.9 percent, leading declines onshore.

In Hong Kong, the Hang Seng Index lost 1.73 percent to the lowest since Mar 4, while the Hang Seng Tech Index tumbled over 3 percent to the lowest level in one-and-a-half months.

Market heavyweight Alibaba slid 3.6 percent and Xiaomi tumbled 4.8 percent. CK Hutchison fell as much as 4.7 percent after likely ports deal signing delay.

Trump is set to announce a massive tariff plan targeting all countries on Wednesday, on top of increased tariffs on all goods from China, he said over the weekend.

China is facing "a stress test" as the markets now expect Trump to announce more reciprocal tariffs on April 2, analysts at Citi said in a note to clients on Monday.

Around the region, MSCI's Asia ex-Japan stock index was weaker by 1.84 percent while Japan's Nikkei index fell 4.08 percent.

Still, the Hang Seng Index has advanced nearly 15 percent so far this quarter on the back of AI optimism and record mainland inflows, on track to rank as the best performer among global major markets.

Elsewhere, China's manufacturing activity expanded at the fastest pace in a year this month with new orders boosting production, giving the world's No. 2 economy some reprieve as it deals with an intensifying US trade war.