North Korea is warning of a nuclear war on the Korean peninsula.
The Communist regime vowing to ramp up its atomic bomb-making despite new UN sanctions.
With tensions mounting, the president of South Korea will meet with President Obama in Washington Tuesday.
Anti-North Korea protestors gathered in Seoul, South Korea Sunday.
They set fire to the North Korean flag and burned posters.
The protestors denounced North Korea's recent nuclear test -- and called on the international community to keep up the pressure on the North.