Japan, the United States, Australia and India are seeking to underscore respect for the sovereignty and territorial integrity of all nations amid Russia's invasion of Ukraine when their leaders meet and issue a joint statement later this month, sources close to the matter said Friday.

The summit of "the Quad" leaders, the second in-person meeting of its kind, will take place in Tokyo on May 24 at a time when cohesion among the four major democracies is being tested by Moscow's aggression, as India historically has close ties with Russia and stood out by not explicitly condemning its war.

The Quad has so far been establishing itself as a group committed to promoting a free, open, rules-based order "undaunted by coercion" and signaled cooperation among the four countries in the Indo-Pacific, where China is expanding its clout as a rising power.