Campbell had been expected to warn Sogavare against the deal, the details of which have not been publicly disclosed, but that was pre-empted days before his visit when Beijing and Honiara announced they had already signed it. According to a draft leaked online in March, the deal allows China to send police and armed forces to the Solomon Islands “to assist in maintaining social order” and Chinese warships to make stopovers there.

The deal is a “game changer,” said Anne-Marie Brady, a China expert at the University of Canterbury in New Zealand.

“The U.S. is the main target of this move, as it aims to counter U.S. containment strategy in the Indo-Pacific,” she said. “But it also directly threatens the security and autonomy of the island states of the Pacific, as well as Australia and New Zealand.”

Among their concerns is that the deal could enable China to set up a military base — its first in the Pacific — less than 1,300 miles from Australia, whose relations with Beijing are at their lowest point in years. The Solomon Islands also sit on key shipping lanes between the U.S. and Asia.