The last move is not allowed by the DPA, that is to say the President cannot order goods made in other countries to be delivered to the US. Whether he can demand a company to cease exports is unclear, however 3M argues it would not be humanitarian. They're exporting products that have been ordered earlier and are desperately needed in both Canada and – even more – in Latin America, where COVID-19 is beginning its devastation.
There's one more possible issue with Trump's request from 3M. If the company is asked not to export abroad from the US, other countries might do the same and demand 3M not to export from their territories to the US. And while 3M has its headquarters based in St. Paul, MN, it's a global company with vast majority of its manufacturing based in Asia. So, simply, if Asian countries retaliate, Americans would get even fewer masks instead of more. And that could prove devastating.
3M is hoping to avoid such problems and asks the President to rethink his request. “We look forward to working closely with the Administration to implement yesterday’s DPA order. We will continue to maximize the amount of respirators we can produce on behalf of U.S. healthcare workers, as we have every single day since this crisis began.” the company's statement ends.