North Korean leader Kim Jong-un attended a massive banquet to congratulate the scientists and engineers involved in the country’s sixth nuclear test a week ago.

The North’s official Korean Central News Agency (KCNA) reported on Sunday that the North Korean Workers’ Party’s Central Committee and the Central Military Commission organized a special banquet for the nuclear scientists and engineers who contributed to the successful test of a hydrogen bomb that can be mounted on an intercontinental ballistic missile.

During the banquet, Kim praised the scientists, saying that the recent test of the hydrogen bomb means a great victory won by the North Korean people at a cost of their blood and tightened belts in the arduous period.

Kim also lauded the participants as achieving the final victory for the country, saying that the feat was achieved on the basis of a solid self-sufficient economy, a large force of scientists with great minds, the Army and the people armed with the revolutionary spirit.

The report said that a congratulatory art performance was held on the sidelines of the celebration, which was attended by Kim and his wife, Ri Sol-ju.

KCNA did not specify when the banquet was held, but it appears to have been held on Saturday to mark the 69th anniversary of the North’s founding day.