WASHINGTON — The Trump administration said on Monday that it would delay a decision to impose steel and aluminum tariffs on the European Union, Canada and Mexico for another 30 days, giving key allies a reprieve as the White House tries to extract concessions from trading partners who have resisted those demands.

The extension reflects concerns by the Trump administration of a swift retaliation on American products by European Union nations, and will also give the Trump administration more breathing room to work on a separate trade battle with China.

The 25 percent tariffs on steel and 10 percent on aluminum were set to go into effect on Tuesday and had set off a global scramble by nations trying to secure permanent exemptions. The administration, which granted temporary exemptions to a handful of countries in March, said it had reached initial agreements with Argentina, Australia and Brazil that would allow them to avoid the tariffs, at least for now. Details of those agreements will be finalized in the next 30 days, the White House said.

President Trump’s decision puts off a move that could have enraged key American allies at a delicate moment, as the United States heads toward tricky negotiations with North Korea and is considering abandoning the Iran nuclear deal over the objections of European Union leaders. Despite the president’s tough stance on trade, many of his advisers are leery of initiating trade clashes that could destabilize stock markets and put other political goals at risk, like updating the North American Free Trade Agreement. The White House is also dispatching a delegation of top officials to Beijing this week to try to soothe tensions in its trade battle there.