SEOUL—North Korea launched a multistage rocket Friday morning, again defying countries that want it to stop pursuing advanced weapons, but it blew up less than two minutes into flight and parts crashed in the Yellow Sea off South Korea.

Despite the failure, the U.S. and its allies quickly condemned the launch, with the White House saying that a food agreement it had reached with Pyongyang in February was dead. But the launch also denied North Korea a key propaganda victory...