Exclusive: poll across 15 countries finds ‘deep mistrust’, with majority doubting US would come to their aid in an attack

European confidence in an American “security guarantee” has hit a historic low, a survey suggests, with only one in 10 people across 15 countries seeing the US as an ally and majorities in all doubting it would come to their aid if they were attacked.

The survey, published on Wednesday by the European Council on Foreign Relations (ECFR) thinktank before critical G7 and Nato summits in France and Turkey over the coming weeks, revealed “deep European distrust in the US”, the authors said.

Explosions reported across Iran after Donald Trump vowed to ‘hit them hard again’, with Bahrain, Kuwait and Jordan targeted by Tehran

• Middle East crisis – live updates

The US launched a new round of airstrikes on Iran into Thursday morning after Donald Trump warned Tehran would “pay the price” for stalled negotiations, prompting Iran to respond with strikes targeting Bahrain, Kuwait and Jordan.

The new US assault across a range of Iranian cities came as efforts to negotiate an end to the war again appeared stuck, with Iran insisting it would maintain its chokehold on the strait of Hormuz. The American attack appeared more intense and wider than the day before, but Iran released no information about what was hit.