China and the Cook Islands on Friday signed a comprehensive strategic partnership agreement, but the lack of transparency around the details has alarmed New Zealand, the South Pacific state’s closest democratic ally.

The Cook Islands said on Saturday that it signed a comprehensive strategic partnership deal with China - a move expected to raise concerns in New Zealand with which it has constitutional ties. The deal was signed by Cook Islands Prime Minister Mark Brown during a visit to Beijing.

No details have been released, but analysts and environmentalists fear it will pave the way for closer security ties and the start of deep-sea mining.

Official ratification of a "comprehensive strategic partnership" agreement is likely to cause consternation in Wellington.

China is willing to deepen mutual political trust with the Cook Islands, China's Premier Li Qiang said during a meeting with Cook Islands Prime Minister Mark Brown, China's national television broadcaster reported on Friday.

Prime Minister Mark Brown of the Cook Islands visited China to discuss marine science, climate resilience, and economic cooperation. The trip, which raises security concerns in New Zealand, includes plans to sign a strategic partnership.

China signs an agreement with an island nation. America’s regional partners get spooked. The Cook Islands, a sparsely populated string of 15 islets, is the latest to set off alarm bells. Its prime minister,

China acknowledged a visit by the Cook Islands leader for the first time on Thursday, amid exasperation in New Zealand that it was not consulted about expected agreements involving the South Pacific nation,