Story highlights Dunford said North Korea "poses the greatest threat today"

China and the US regularly test and challenge each others' power

(CNN) America's top military officer, Gen. Joseph Dunford, told Congress Tuesday China is likely to be the "greatest threat" of any foe to the US within a decade.

"I think China probably poses the greatest threat to our nation by about 2025," Dunford told the Senate Armed Services Committee during a hearing on his re-appointment as Chairman of the Joint Chiefs of Staff.

Dunford was responding to a question from Hawaii Democrat Sen. Mazie Hirono, who noted that the general had previously identified Russia, followed by China and North Korea, as representing the greatest military threats to US national security during a 2015 appearance before the same committee.

But on Tuesday Dunford took the opportunity to reshuffle his list of national security concerns, saying that North Korea now "poses the greatest threat today" due to the "sense of urgency" involved as Pyongyang's develops its nuclear and missile programs.

He also said that Russia remained the greatest threat overall due to its military capabilities in the realms of nuclear weapons and electronic warfare as well as Russian military activity in places like Crimea, which it invaded and annexed in 2014, and eastern Ukraine, where Western officials accuse Moscow of backing armed separatists.