Prime Minister Fumio Kishida and British Prime Minister Boris Johnson agreed in principle Thursday on a defense cooperation pact as part of their efforts to realize a "free and open Indo-Pacific," in a veiled counter to an increasingly assertive China.

A reciprocal access agreement (RAA), when signed, would enable faster deployment of their troops and allow them to engage in joint training and disaster relief efforts. Japan recently signed a similar RAA with Australia.

Kishida expressed appreciation for Britain's increased involvement in the Indo-Pacific region, and the two leaders expressed "strong concern" about unilateral attempts to change the status quo in the East and South China seas and "rapid but not transparent" military buildup and activities, the Japanese government said.