Prime Minister Shigeru Ishiba wants to separate negotiations on tough U.S. tariffs from security-related discussions — but disentangling the two will prove a challenge as U.S. President Donald Trump continues to voice long-held complaints about the alliance’s fairness.

Ishiba has repeatedly said over the last week that the two issues must be dealt with separately, following Trump’s latest gripes that the 65-year-old security alliance is “one-sided.”

“Tariff negotiations are tariff negotiations. National security discussions are national security discussions,” Ishiba told lawmakers on Monday. “If we don’t keep them separate, I believe we risk distorting the essence of each issue.”