Prime Minister Yoshihide Suga spoke with U.S. President-elect Joe Biden on Thursday morning for the first time since the latter won the U.S. presidential election, with Tokyo saying that the soon-to-be-inaugurated leader reassured Suga that his administration will commit to protecting the Senkaku Islands under their security alliance.

Speaking to reporters after the roughly 15-minute teleconference, the prime minister said the president-elect made clear that Article 5 of the U.S.-Japan Treaty of Mutual Cooperation would apply to the Senkaku Islands, which China claims and calls the Diaoyu Islands. The article states that the U.S. would defend the territories under Japan’s administration in the event of an armed attack.

The apparent affirmation by Biden on the Senkaku Islands, which was previously re-emphasized by President Barack Obama around the time Chinese vessels began entering waters near them, brings a sigh of relief for Tokyo officials as they monitor Biden’s approach to China with a mix of expectation and trepidation.