Experts of the International Atomic Energy Agency (IAEA) monitoring the shutdown of nuclear facilities in North Korea said Wednesday the mission was on time after initial delays due to radioactive contamination, according to dpa. "We completed this step of our mission. This kind of monitoring and verification issues is of a continuous nature. We were already able to fulfil our planned activities and we are going to headquarters to evaluate and assess what we did," IAEA team leader Adel Tolba told journalists after arriving at Vienna airport. Tolba added that verification and monitoring activities would be ongoing, and the results would be presented to the IAEA Board. Reacting to news reports about radioactive contamination found by his team at the Yongbyon nuclear site, Tolba confirmed initial contamination levels slightly above average, but added this was a normal occurrence, "not unexpected" by the IAEA experts. "This is a contamination which you can find in any nuclear facility. But that degree of contamination was a little bit higher than normally. It is not like we find something unexpected. This is normal contamination which we work with ... in nuclear facilities everywhere." The contamination had since then been cleared and while it originally delayed the team's work, they were now back on schedule. "We are in time," Tolba said. The IAEA team praised Pyongyang's cooperation in their efforts: "Cooperation was very satisfactory," Tolba said. "We were able to conduct all our work because of that cooperation" The team had been in North Korea since July 14, verifying that North Korea shut down all five nuclear facilities at the Yongbyon nuclear complex. On Monday the original monitors were replaced by a second IAEA team. In February, North Korea agreed to mothball its nuclear weapons programme in exchange for far-reaching economic and energy aid. The shutdown of the Yongbyon reactor and the other facilities was however held up by North Korean demands to unfreeze assets believed by the US to originate from counterfeiting and money laundering activities, that were held at a bank on Macao. In the latest round of the six-party talks held in July, the participating countries Russia, China, Japan, the United States and the two Koreas agreed that further talks will be held in September. Despite the lack of a fixed timetable, they are still upbeat that progress will be possible.