Updated

President Donald Trump and North Korea's Kim Jong Un spent Monday huddling with advisers in luxury Singapore hotels less than half a mile apart, readying for a nuclear summit that could define the fate of millions, and their own political futures.

Both sides also worked to finalize preparations for the unprecedented summit.

The meeting was kicking off at 9 a.m. Tuesday with a handshake between Trump and Kim. A U.S. official says the leaders then plan to meet one on one, joined only by translators, for up to two hours before admitting their respective advisers.

The official was not authorized to speak publicly about internal deliberations and insisted on anonymity.

Tuesday's summit will be the first between a North Korean leader and a sitting American president.