Japanese equities started Monday with a decline, tracking losses in US equity-index futures, as President Donald Trump announced plans to double tariffs on steel and aluminum imports.

The Nikkei 225 index opened 313.92 points lower, settling at 37,651.18.

Meanwhile, oil prices rose as geopolitical tensions outweighed an increase in supply from OPEC+.

Domestically, Japanese businesses accelerated their capital investment in the first quarter of the year, even as the Trump administration initiated its tariff campaign in March.

The Ministry of Finance reported Monday that capital expenditure on goods (excluding software) increased by 1.8% in the three months ending March, an acceleration from the 1.3% rise in the previous period.

This figure surpassed the 1.4% gain in corporate investment noted in Japan's preliminary gross domestic product (GDP) report. The updated data will be incorporated into the revised GDP report scheduled for release on June 9.