WASHINGTON—President Donald Trump eased trade pressure on top U.S. allies Monday, giving the European Union and some nations outside the bloc more time to negotiate deals that would exempt them from U.S. steel and aluminum tariffs.

The White House said broad tariffs of 25% on steel and 10% on aluminum—already in effect against China, Russia, Japan and others—won’t take effect for the EU Tuesday as previously planned. Instead, Europe will have an additional month to keep talking with the U.S. about a new pact to avoid the tariffs.

...