The Tánaiste has said he fears Donald Trump could yet tear up the US-EU trade deal agreed last month.
In July, European Commission President Ursula von der Leyen flew to meet the US President at one of his Scottish golf courses, where they agreed that most EU products imported into America would pay a 15% tariff.
By contrast, many US exporters will pay no tariffs when they sell their products to European customers.
On Newstalk Breakfast, Tánaiste Simon Harris said the terms of the deal might yet change.
“This is only, at best, a framework agreement,” he said.
“What you’ve basically seen the Trump Administration do is agree at a high level headline rates of tariffs, so the headline rate of tariff for the EU - including Ireland - being 15%.
“I welcome the limited degree of certainty that provides because businesses have been constantly saying, ‘What will it be? We’ve heard all sorts of figures.’
“So, we have a degree of certainty now that the headline tariff rate is 15% and it’s in now.”

Last year, total Irish exports were valued at €223.8 billion, of which €72.6 billion were sold to the United States.
When Mr Trump threatened tariffs of 30%, Minister Harris admitted this would effectively ‘stop trade from functioning’ between Europe and America.
While a doomsday scenario for exporters has been avoided, the Fine Gael leader said that he still believes tariffs are a “bad idea”.
“There’s a huge amount of details that still needs to be worked out and teased through in the time ahead,” he explained.
“So, for example, there are some sectors where we have agreed with the United States that there’ll actually be zero tariffs.
“Certain sectors like aviation - that’s really quite important to Ireland; we’ve a very vibrant and large aircraft leasing sector here in this country.
“There’s also other sectors where the US is open to having a conversation on making progress - including spirits; that’s very important for the Irish drinks industry, the med tech sector.”

Much of the recent surge in demand for Irish products is driven by the huge increase in Americans taking weight loss medication.
In a bid to force US pharma companies to make more of their drugs in America, Mr Trump has speculated that he could impose 250% tariffs on imported medication.
It all means, Minister Harris conceded, that there is still a “lot of work to do” ironing out the details of what the EU-US agreement means for the pharmaceutical sector.
“What they’re said in the framework agreement is that tariffs on pharma made in the EU will be no higher than 15%,” he said.
“Again, that’s not the full story because the pharma sector operates in a global market.
“If he starts putting much larger tariffs on other parts of the world, what impact does that have on global supply chains?
“So, there’s a very significant way to go on this is the honest answer.”
Minister Harris vowed to continue “engaging intensively” with US officials and business stakeholders.
Main image: Taoiseach Micheál Martin with US President Donald Trump in March. Picture by: Tasos Katopodis / Government of Ireland.