Singapore shares experienced a slight downturn on Tuesday, influenced by global market anxieties stemming from US President Donald Trump's proposal to impose taxes on all countries.

Straits Times Index, a key indicator of the Singapore Exchange's performance, traded within a range of 3,938.43 and 3,980.28 throughout the session. By the market's close, the index settled at 3,968.850, representing a decrease of 3.58 points, or 0.09%.

The lackluster sentiment came as Trump said his "reciprocal tariffs" plan, which is expected to be unveiled this week, will target all countries.

In company news, shares of BH Global surged over 20% after its subsidiary, Sea Forrest International, filed for an initial public offering on the Nasdaq.

CapLand Ascendas REIT was up nearly 2% after it completed the redevelopment of 1 Science Park Drive for SG$883 million.

Meanwhile, Kep Infra Tr was down over 1% at the close after the trust agreed to acquire 46.7% of the enlarged capital of Pangea UK Holdco, which indirectly holds 100% of Global Marine Group for a total consideration of $90.6 million.

STI fell 0.1%; Singtel up 4%; Sembcorp up 1.3%; Seatrium fell 4.3%; Nio fell 3.3%; Yangzijiang Shipbuilding, SGX fell 2%.