Panamanian investigators unloading the cargo of a seized North Korean ship that carried arms from Cuba have found the two MiG-21 fighter jets the Cuban government said were on board. Beside the planes, originally produced by the Soviet Union in the late 1950s, officials found two missile radar systems, President Ricardo Martinelli said. They were inside containers Panama had feared might contain explosives, none of which was found. After stopping the Chong Chon Gang bound for North Korea last week, Panama said it had found weapons in the hold. Cuba said the cargo contained a range of obsolete arms being sent to North Korea for repair. Panama has asked the UN Security Council to investigate the ship on suspicion it is in breach of a wide-ranging arms embargo on North Korea for its nuclear and ballistic missile programme. "One can't take undeclared weapons through the Panama Canal below other cargo," Martinelli said, adding that he had not spoken to any Cuban officials since they first asked for the ship to be released last Saturday. Javier Caraballo, Panama's top anti-drugs prosecutor, said the planes smelled strongly of fuel, indicating they had probably been used recently. Panama had not found anything not on the Cubans' list, he added. The UN team is expected to arrive in August after Panama finishes unloading the 155-metre ship. The weapons were hidden under thousands of sacks of sugar. Before the arms were discovered, Cuba told Panama the cargo was a donation of sugar.