WASHINGTON—After moving to the precipice of military action against Iran, President Trump finds himself caught between negotiations that show few signs of yielding a nuclear deal and a war he is reluctant to join.

Hours of talks aimed at de-escalating fighting between Israel and Iran failed to produce a diplomatic breakthrough as the war entered its second week with a fresh round of strikes between the two adversaries.

President Donald Trump will decide in the next two weeks whether the U.S. will get involved in the Israel-Iran air war, the White House said on Thursday, raising pressure on Tehran to come to the negotiating table.