Dozens of armed special police officers clad in combat fatigues and flak jackets, their faces hidden by balaclava masks, sealed off the central Moscow highrise office building which houses MOST-Bank late Friday afternoon and arrested several men. Moscow city officials, a MOST-Bank spokesman and the militia stationed outside the building at 36 Novy Arbat said Friday night they did not know what branch of government forces had conducted the operation which was continuing as of late Friday night. The raid, made extraordinary by the fact that nobody explained why it was happening or who did the arresting, stopped rush hour traffic on Novy Arbat and attracted swarms of journalists and bystanders who witnessed the detentions. MOST-Bank head Vladimir Gusinsky told Interfax late Friday that up to 10 of his bodyguards and chauffeurs were taken into custody by the special officers and brought to a local police station.