BRUSSELS — European governments may believe Iran is to blame for the attacks this week on fuel tankers in the Gulf of Oman, but their distrust of the Trump administration and its hawkish policy toward Tehran have led them to measure their words and call for de-escalation and “maximum restraint.”

Mindful of Washington’s exaggerations and outright misrepresentations of intelligence leading up to the Iraq war, European leaders are asking the Trump administration for hard evidence. The last thing they want is to be asked to support another American war in the Middle East that would be highly unpopular with voters.

Europeans are no fans of the Iranian government or its policies in the Middle East, but they are concerned by what they see as the Trump administration’s policy of “maximum pressure” on Iran — thus their use of maximum restraint. Many critics believe Mr. Trump is succeeding only in creating maximum pressure among hard-line factions in Iran to respond with carefully calibrated attacks that send a message, like those against tankers in a vital passageway for global oil supplies.

Germany wants a careful investigation of the attacks, insisting that “a spiral of escalation must be avoided.” The European Union, in the words of the spokeswoman Maja Kocijancic, has “said repeatedly that the region doesn’t need further escalation, it doesn’t need further destabilization, it doesn’t need further tension.”