The comments mark a shift in his approach to the war and come as his frustration with Russian President Vladimir Putin’s continued aggression has grown.

Berlin is in talks with Washington to buy two U.S.-made Patriot air defense batteries and interceptors for Ukraine, German Defense Minister Boris Pistorius told the Financial Times on July 13.

The US president did not specify the number of Patriots he plans to send to Kyiv, but said that the cost would be fully ...