Hundreds of U.S. Marines and sailors, Australian soldiers and Japanese Self-Defense Force members are conducting a major warfighting exercise in Australia.

Shoalwater Bay, where the training is taking place, is an arena for the biennial Talisman Sabre exercise, which involved 17,000 U.S., Australian, New Zealand, Japanese, South Korean and British troops last summer.

Australian politicians reacted with alarm earlier this month after revelations that the Solomon Islands, 1,200 miles northeast of Shoalwater, was negotiating a security pact with China.

Australian Prime Minister Scott Morrison refused to say how his government might respond if China attempted to establish a military base in the islands.

The exercise has taken place each year since 2015.