Kim Jong Un poses beside possible nuclear warhead mock-up

SEOUL — North Korea caused a new stir Wednesday by publicizing a purported mock-up of a key part of a nuclear warhead, with leader Kim Jong Un saying his country has developed miniaturized atomic bombs that can be placed on missiles.

The North’s Rodong Sinmun newspaper carried photos on its front page showing Kim and nuclear scientists standing beside what outside analysts say appears to be a model warhead part — a small, silverish globe with a ballistic missile or a model ballistic missile in the background.

The photos come amid heightened tensions after the United Nations imposed harsh sanctions on North Korea for its nuclear test and long-range rocket launch earlier this year.