A plane with a shipment of over one million N95 masks from China.

PARIS: From Europe to South America, US allies are complaining about the superpower's "Wild West" tactics in outbidding or blocking shipments to buyers who have already signed deals for vital medical supplies.

In France and Germany, senior officials said the United States was paying far above the market price for medical-grade masks from No. 1 producer China, on occasion winning contracts through higher bids even after European buyers believed a deal was done, and Brazil's health minister reported a similar incident.