"I wouldn't say there's a concern there," said the official, who spoke on condition of anonymity because he wasn't authorized to discuss the matter publicly.
"I mean, we're down into the final rounds of discussion, and it's always difficult at the end."
Potentially compounding those difficulties is the fact that European negotiators will now direct most of their attention to a trade agreement with the Americans.
U.S. President Barack Obama hinted at the rocky road ahead for American and European negotiators.
"There are going to be sensitivities on both sides. There are going to be politics on both sides," Obama said Monday.
"But if we can look beyond the narrow concerns to stay focused on the big picture, the economic and strategic importance of this partnership, I'm hopeful we can achieve the kind of high-standard, comprehensive agreement that the global trading system is looking to us to develop."
Obama added he's sure he and EU leaders will have to step in sometimes to break deadlocks in the negotiations.
"It is important that we get it right. And that means resisting the temptation to downsize our ambitions or avoid tough issues just for the sake of getting a deal," Obama said.
"We're going to give a strong mandate to our negotiators, but occasionally I suspect we're going to have to intervene and break through some logjams. Nevertheless, I'm confident that we can get it done."
Jose Manuel Barroso, president of European Commission, also spoke of the difficult task facing negotiators.
"Integrating two of the most developed, most sophisticated and certainly the largest economies in the world can never be an easy task," Barroso said.
"But we will find convincing answers to legitimate concerns. We will find solutions to thorny issues. We will keep our eyes on the prize, and we will succeed."
British Prime Minister David Cameron, who is chairing the G8 summit in Northern Ireland where the start of the talks was announced, underscored the potential magnitude of a U.S.-EU trade deal.
"We're talking about what could be the biggest bilateral trade deal in history, a deal that will have a greater impact than all the other trade deals on the table put together," Cameron said.
"We must maintain that political will in the months ahead. This is a once-in-a-generation prize, and we are determined to seize it."
Among the obstacles believed to be standing in the way of a free-trade deal between Canada and the EU is access to European markets for Canadian beef.
France and Ireland — two major beef producers — are said to object to the amount of beef Canada wants allowed into Europe.
Harper was in both countries ahead of the G8 summit in Northern Ireland.