North Korea is threatening to add to its nuclear arsenal if talks with the United States and its allies are delayed.
It also said Washington was "wasting time" by rejecting Pyongyang's offer to freeze its nuclear arms programme.
China weighed in on the side of its old communist ally, urging the United States to be more flexible in the next round of six-party talks aimed at ending the North Korean nuclear crisis, Xinhua news agency reported.
North Korea's ruling party newspaper today criticised Washington for rejecting the North's proposal last week for a "simultaneous package solution" under which Pyongyang would freeze its nuclear programme in exchange for energy aid.
"The US wasting time would do the DPRK nothing bad," said the Rodong Sinmun. "Its delaying tactics would only result in compelling the DPRK to steadily increase its nuclear deterrent force," said the newspaper in a report published by the official KCNA news agency.
DPRK stands for the Democratic People's Republic of Korea, communist North Korea's official name.