China is drawing a link between nuclear nonproliferation talks and a Western submarine pact in the Pacific that it opposes, potentially adding another obstacle to the tortured process of reaching a deal with Iran.

Beijing had already emerged as a linchpin to the success or failure of talks resuming Monday in Vienna on how to restore the 2015 nuclear accord between Tehran and world powers.

The decision by China’s envoy at the International Atomic Energy Agency this week to elevate Beijing’s concerns over the so-called AUKUS atomic submarine deal between the U.S., U.K. and Australia alongside international worries about Iran’s nuclear program suggests Chinese ambitions are growing.