WASHINGTON, D.C.: A landmark nuclear submarine pact between the United States, Australia and Britain underscores concerns over growing Chinese military power, but it will be years before the new vessels can help counter Beijing's efforts to expand its reach and influence.

The deal — part of an agreement known as Aukus — will see Australia replace its diesel-powered submarines with nuclear-powered ones that have far greater stealth and range, first through purchases from the United States and later with domestically produced vessels.