In a recent interview with TIME, Trump said some types of ammunition were below normal levels, while insisting that the United States remains in a strong position.
Trump said the US is increasing weapons production and working to rebuild its stocks on a large scale.
His comments come after US military operations in Iran consumed significant quantities of missiles and other weapons.
A Pentagon inspector general report previously warned that the conflict had contributed to shortages of important munitions and exposed difficulties in replacing them quickly.
The report estimated that more than $22 billion had been spent on munitions during the early months of the Iran operation.
Trump disputed some of the concerns surrounding the reported shortages, saying the United States has substantial weapons supplies and is continuing to manufacture more.
He also pointed to efforts by major defence manufacturers to expand production facilities across the country.
The United States has been increasing orders for systems including Patriot and THAAD interceptors, as well as other missiles, amid concerns about military stockpiles.
The Pentagon has also pursued major contracts aimed at increasing production of key weapons.
The latest developments highlight the pressure facing the US defence industry as Washington continues military operations while also supporting allies with weapons.
Trump said the United States would continue rebuilding its stocks and described the planned production levels as unprecedented.