Rutte, known in Europe as a "Trump whisperer", is working to defuse a crisis after Trump said he was considering withdrawing from the 32-member transatlantic military alliance, arguing that European allies have relied on US security guarantees while providing inadequate support for the US-Israeli bombing campaign in Iran.
Three diplomats told Reuters that Rutte, who met with the US president at the White House on Wednesday, conveyed Trump's demands to European countries.
European leaders are under pressure to show they are quickly making tangible plans to help secure the Strait of Hormuz, which is a vital oil transit point that Iran has effectively blocked during the conflict.
Speaking in Washington DC a day after meeting Trump, Rutte said that some alliance members were initially "a bit slow" to provide assistance to the US in Iran and "a bit surprised" but that now there is a "massive amount" of support including basing and logistics.
"Nearly without exception, allies are doing everything the United States is asking. They have heard and are responding to President Trump's requests," Rutte said in a speech hosted by the Ronald Reagan Institute.
Multiple European allies have said they are willing to help in the Strait of Hormuz but only once there is a durable cessation of hostilities and an agreement with Iran that their ships will not be attacked.
NATO spokeswoman Allison Hart said on Thursday: "The secretary general is in contact with allies about his discussions in Washington" and "it's clear that the United States expects concrete commitments and action to ensure freedom of navigation in the Strait of Hormuz".
In his speech, Rutte said the military alliance is undergoing a shift but growing stronger.
"Allies recognise, and I recognise, we are in a period of profound change in the transatlantic alliance. Europe is assuming a greater and fairer share of the task of providing for its conventional defence," Rutte said.
