FOUR Ukrainians were on a United Nations helicopter seized by al Shabaab militants in central Somalia this week, Ukraine's foreign ministry said. The U.N.-contracted chopper with nine aboard was conducting a medical evacuation when a technical problem forced it to land near Hindhere village, an area controlled by the Islamist group. "Our citizens were members of the helicopter crew of the UN Mission in Somalia ... Their identities have been established," Ukrainian spokesman Oleh Nikolenko wrote on Facebook. He said the aircraft belonged to a private Ukrainian company contracted to the United Nations, and that the government was contacting it to…