Singapore shares plunged on Monday, tracking regional losses as the US-Iran conflict took a new turn with the US Treasury Secretary Scott Bessent expected to provide details of Washington's "economic D-Day" play for Iran.

The Straits Times Index (STI), a key benchmark for the Singapore Exchange, ranged between 5,673.71 and 5,715.47 throughout the day. It ended the session at 5,680.46, down 8.50 points or 0.2% compared to Friday's close.

In economic news, Singapore's core consumer price index (CPI), which excludes accommodation and private transport costs, rose 2% year over year in July, according to joint data released by the Monetary Authority of Singapore (MAS) and the Ministry of Trade and Industry (MTI).

On the corporate front, shares of OUE Healthcare (SGX:5WA) surged over 23% at the close as it received a proposal to be taken private via a scheme of arrangement, with scheme shareholders to receive SG$0.050 per share.

iX Biopharma's (SGX:42C) shares dipped nearly 9% at the close as its net loss attributable to equity holders widened 196% to SG$5.0 million during the fiscal fourth quarter ended June 30 from SG$1.7 million a year earlier.

Meanwhile, Pacific Century Regional Developments (SGX:P15) subsidiary, PCRD Services, agreed to sell its indirect 49.87% stake in India's KSH Distriparks to Delhi International Cargo Terminal for around SG$19.3 million.