Negotiations on the Transatlantic Trade and Investment Partnership (TTIP) between the European Union (EU) and the United States are set to continue in July, according to the American Farm Bureau Federation (AFBF).

The national organization’s trade specialist, Dave Salmonsen, says agricultural issues—like eliminating tariffs for U.S. products and geographic indicators—must be resolved to complete the deal.

“These are the kinds of things that are still under contention and are looming as continuing barriers move ahead on the ag section. So, these have been issues that have been going on, but flared up even more recently,” he said.

The talks next month will likely focus on eliminating EU tariffs.

“These are classic issues to talk about in trade and I think there’s a desire to try to get an agreement on something,” Salmonsen said. “Removing tariffs is important, always, and still important in agriculture in our trade with the European Union.”

But political issues—U.S. presidential election and the vote in Britain to consider leaving the EU—could impact the negotiations going forward.

“The referendum in Britain is on June 23. Depending on the outcome, that could lead to a lot of uncertainty over the future of the European Union,” he said. “And, of course, some of the positions on trade issues from some of the presidential candidates leads to uncertainty on the European Union side about how this TTIP deal will progress in the future after the end of the Obama administration.”