BRUSSELS — As tensions between Washington and Tehran escalate, European leaders find themselves in an uncomfortable place they have feared ever since President Trump pulled out of the Iran nuclear deal 13 months ago and restored punishing sanctions against Tehran.

While the Europeans want to preserve the deal — which they see as important for their own security and for the stability of the Middle East — they are basically powerless in the face of American military and financial clout.

Iran is calling on Europe to solve its economic problems brought on by the sanctions or face a collapse of the nuclear deal as Iran begins to exceed limits on uranium enrichment. But Washington wants the Europeans to join in pressing Iran to enter humiliating new negotiations to shut down Tehran’s nuclear program entirely, limit its missile programs and restrict its regional ambitions.