Foreign Minister Taro Kono found himself in a tough spot on his recent trip to the Middle East, seeking to reconcile Japan's potential as a mediator in the region with its loyalty to Washington in the wake of the U.S. decision to recognize Jerusalem as the capital of Israel.

This dilemma saw Kono, who has pushed Japan's potential to contribute in the Middle East since he took up his post in August, restrain his typical straight-talking manner while in Bahrain and the United Arab Emirates over the weekend.

"If we fall in line with Middle Eastern countries, we'll provoke resentment from the United States," Japan's top ally, a government source said, explaining Tokyo's concerns in the face of the nuclear and ballistic missile threat from North Korea.