U.S. President Barack Obama held a 40-minute teleconference with Prime Minister Shinzo Abe on Wednesday morning, during which he apologized for "causing trouble" in relation to leaked documents showing alleged spying by the U.S. National Security Agency on high-level Japanese officials and companies.

Chief Cabinet Secretary Yoshihide Suga made the announcement but he did not say whether Obama admitted the U.S. had spied on Japanese officials and companies, as alleged in the documents released by the anti-secrecy group WikiLeaks earlier this month.

Obama said he knows the leaked documents caused a big stir in Japan and apologized for the trouble, Suga told a daily press briefing.