Ukraine has said it is doing everything possible to secure the extradition from Libya of 19 of its citizens accused of being pro-Gaddafi mercenaries. The group, which also includes three Belarusians and two Russians, was formally charged on Monday, eight months after they were detained. The 24 accused insist they were working as oil industry contractors. One of the Russians told UK broadcaster the BBC that they had all been in Libya purely to service oil rigging equipment and that a good lawyer would "easily refute the case". They also denied charges of preparing land-to-air missile launchers to shoot down planes taking part in the NATO-led mission to help rebelling civilians. The Russian embassy in Libya also said it was doing all it could to secure the release of its citizens. Belarus said its three citizens had signed contracts to operate civil facilities in Libya and it was co-ordinating its efforts with the Russian and Ukrainian embassies. The Ukrainian authorities said negotiations between Kiev and the Libyan authorities were already under way. A spokesman for the Ukrainian foreign ministry said a possible extradition of its citizens was on the table, even though the two countries had no formal treaty. The group who were detained as rebel fighters pursued the remnants of pro-Gaddafi forces last September are now being held near Tripoli at a Libyan Home Guard base.