North Korea vowed on Sunday to launch a second space rocket after calling last month's botched attempt at launching a satellite the "gravest failure."

The North Korean government has ordered researchers and other workers to analyze the failed launch and prepare for another one in the future.

The comments were made at a key meeting for the ruling Workers' Party of Korea in Pyongyang that ran from Friday to Sunday.

Party officials at the meeting "bitterly criticized the officials who irresponsibly conducted the preparations for (the) satellite launch," state news agency KCNA said.

North Korea claims 'strides' in nuclear program

At the meeting, officials said North Korea was making "big strides" in developing nuclear weapons and continued to strengthen ties with countries that oppose what it called the "US strategy for world supremacy."

The Politburo members also analyzed the "extremely deteriorating security situation" in the region caused by the "reckless war moves" of its rivals, apparently referring to the expanded US-South Korea military drills, KCNA said.

It said they unanimously approved unspecified plans for counteraction.

The KCNA report did not say whether North Korean leader Kim Jong Un spoke during the meeting.

A spokesperson for South Korea's Unification Ministry, Koo Byoungsam, said it would be highly unusual for Kim to sit through such a high-profile party meeting without making a public speech.

Koo said the apparent lack of a speech by Kim could stem from the failure of the satellite launch.

The failed launch of May 31 was widely denounced by South Korea, Japan and the United States.

Although Pyongyang said the launch was to put a military reconnaissance satellite into orbit, critics said the rocket technology overlapped with ballistic missile technology and therefore breached sanctions.

South Korea recovered some of the wreckage from the ocean. Seoul hopes the debris can help experts gain insight into Pyongyang's ballistic missile program.