Hanoi: The US-North Korea nuclear summit in Hanoi ended abruptly without a deal on Thursday, with President Donald Trump saying he had decided to "walk" in the face of Kim Jong Un's demands to drop sanctions.

The much-anticipated second meeting between the two leaders was supposed to build on their historic first summit in Singapore, but they failed to sign a joint statement as initially scheduled and the talks ended in deadlock. "Sometimes you have to walk and this was just one of those times," an unusually downbeat Trump said.