President Barack Obama and Japanese Prime Minister Shinzo Abe spoke by telephone Monday evening to discuss their \"grave concern\" about the use of chemical weapons on Aug. 21 in Syria, the White House announced Tuesday. \"The two leaders agreed that the use of chemical weapons is a serious violation of international norms and cannot be tolerated,\" the announcement said. \"They pledged to continue to consult closely on possible responses by the international community.\" The two leaders also reaffirmed the critical role of the U.S.-Japan alliance for the peace and stability of the Asia-Pacific region, the statement said. \"They stressed their shared commitment to taking steps to further enhance security cooperation on regional and global challenges, and to continue implementing our shared plan for U.S. force posture realignment in Japan,\" it said. Obama underscored his view that the Trans-Pacific Partnership negotiations should be concluded this fall, and both leaders agreed to consult closely on the way ahead, the White House said.