The US dollar registered modest gains on Monday as traders assessed the implications of the latest global tariff proposal from US President Donald Trump. Amid escalating US-Iran tensions, safe-haven flows propelled the Japanese yen and Swiss franc to outperform other G10 currencies.

The Bloomberg Dollar Index climbed 0.1%, after having fallen as much as 0.3% earlier in the session.

"At the start of the week, the dollar largely remained within its recent trading range, with market focus centered on uncertainties surrounding US trade policy and the economic impact of a severe winter storm in the US Northeast," analysts at Monex noted.

A powerful storm swept across the US East Coast, leading to widespread flight cancellations at major airports in the region on Monday, including those serving New York and Boston.

USD/JPY declined 0.2% to 154.74, after touching a low of 154.00 earlier. Trading was subdued due to a market holiday in Japan.

Senior US officials attempted to defend the administration's assertive trade policies, stating that a recent legal defeat for Trump at the US Supreme Court regarding tariffs would not invalidate agreements the US has reached with trade partners, including the pact with Japan.

USD/CHF fell 0.1% to 0.7745.

USD/CAD rose 0.2% to 1.3704.

"Canada's exposure to the US economy makes it vulnerable not only to the USMCA negotiations but also to a renewed flare-up in US tariff risks," wrote Wells Fargo strategist Erik Nelson in a report on Monday.

Wells Fargo maintains a preference for selling the Canadian dollar against both the euro and the US dollar.

EUR/USD was largely unchanged at 1.1786.

GBP/USD advanced 0.1% to 1.3490.

AUD/USD decreased 0.3% to 0.7057.