India-Maldives ties strained as Maldives allows Chinese vessel despite India's concerns. Maldives claims vessel won't conduct research. Sri Lanka has a moratorium on research ships. US voices concerns about Chinese research vessels. Maldives reneges on agreement with India for hydrographic surveys.India-Maldives ties strained as Maldives allows Chinese vessel despite India's concerns. Maldives claims vessel won't conduct research. Sri Lanka has a moratorium on research ships. US voices concerns about Chinese research vessels. Maldives reneges on agreement with India for hydrographic surveys.