The dollar posted modest gains against major peers at the start of Asian trading on Monday as rising tensions involving the United States and Iran pushed investors toward safer assets. The firmer greenback came as broader risk appetite remained weak following a turbulent stretch for global markets.

Oil was a central focus, with Brent crude reaching the $90 level as worries over the Middle East conflict raised concerns about supply risk and inflation pressure. Higher energy prices added another layer of uncertainty for investors already dealing with a fragile backdrop.

Sentiment was also weighed down by lingering concerns about lofty semiconductor valuations, which had already unsettled markets last week. That combination of geopolitical stress, rising oil and pressure on high-growth sectors contributed to a cautious tone across financial markets.

Overall, trading reflected a defensive mood, with the dollar benefiting from demand for perceived safety while oil prices extended their advance. The latest moves highlighted how quickly geopolitical developments can ripple through currencies, commodities and broader investor confidence.