The Russian Defense Ministry released a video clip and photos of Tuesday's joint exercise with China along with a statement saying that the mission was aimed at developing Russia-China military cooperation and was not directed at any third country.
The United States has weighed in too sources at the State Department telling VOA that the U.S. strongly supports South Korea and its concerns about the provocative air operations.
The source also said that the U.S. will continue to monitor the situation and discourage attempts to destabilize the region, calling America's commitment to the defense of its allies "ironclad".
Seoul's Joint Chiefs of Staff said Tuesday that a total of 19 military aircraft from Russia and China entered the air defense identification zone, known as KADIZ, though they said the planes did not violate South Korea's airspace.
The South Korean Air Force scrambled fighter jets, as did Japan, which says some planes entered its ID zone too.
Observers say the latest joint exercise by China and Russia is aimed at putting pressure on America and its allies ahead of a new U.S. administration set to start next month.
In a phone conversation Tuesday with his Russian counterpart, Chinese foreign minister Wang Yi condemned the U.S. for in his words "wielding the stick of unilateral sanctions" out of step with the times, and he emphasized Beijing-Moscow cooperation.
Russian foreign minister Sergey Lavrov said that the two countries firmly oppose what he called the undermining of multilateralism by the U.S. and that they will defend their common interests.
Yoon Jung-min, Arirang News.