When it was pointed out to Sanders that the president had tweeted over a dozen times about flags and anthems and other extraordinarily important and pressing sports-related things, while remaining effectively silent on the 3.4 million USA citizens in Puerto Rico who were without power or shelter following hurricane Maria, Sanders bristled.
White House spokeswoman Sarah Huckabee Sanders dubbed the claim "absurd" and clarified that Washington had not "declared war" on Pyongyang.
Sanders also took issue with the suggestion that Pyongyang would have the right to shoot down U.S. planes near North Korean airspace.
The minister said that the United States President Donald Trump has declared war and Pyongyang reserves the right to take countermeasures, including shooting down the US strategic bombers.
Mr Trump's statement at the weekend came after Mr Ri said targeting the United States mainland with its rockets was inevitable after "Mr Evil President" Trump called Kim Jong-un "rocket man".
"Trump's unprecedented rude nonsense one has never heard from any of his predecessors clearly showed the world his true colour as a "political layman", "political heretic" and wrecker of the world peace and security". This is about the president and millions of Americans being for something.
In response, the White House denied that the United States had declared war on Pyongyang.
South Korea has reacted with unease to Trump's threat to "totally destroy" North Korea as its densely-populated capital Seoul is located just 35 miles from the demilitarized zone separating the Korean peninsula. "That's our focus, doing that through both the most maximum economic and diplomatic pressures as possible at this point".
The White House has dismissed North Korea's claim that a tweet by Donald Trump amounted to a declaration of war.
North Korea in recent weeks detonated its sixth nuclear bomb and has test-fired intercontinental missiles - saying it needs to defend itself against hostility from the United States and its allies.
During his address to the General Assembly on Saturday, Mr Ri launched a personal attack on Mr Trump, calling him a "mentally deranged person full of megalomania".