<span style="color: #222222;">Japan is sending a vice foreign minister to the Solomon Islands on Monday amid worry over a recent security agreement that the South Pacific nation struck with China. Vice Foreign Minister Kentaro Uesugi's three-day trip to Solomon Islands comes on the heels of a visit by a senior U.S. delegation, who warned that Washington would take unspecified action against the South Pacific nation should the security deal with China pose a threat to U.S. or allied interests.<br />''</span><br />''The security pact, which China and the Solomons confirmed last week, has also alarmed neighboring countries and Western allies, including Japan, that fear a military buildup in the region.<br />''<br />''Japan sees China's increasingly assertive military activity in the East and South China seas as a threat in some of the world's busiest sea lanes.<br />''<br />''<span style="color: #222222;">Earlier, Senior officials from Japan, the United States, Australia and New Zealand share concerns over a fresh security pact between China and the Solomon Islands.</span><br />