As Russia’s military pressed its efforts to expand into Ukraine’s east, Ukrainian President Volodymyr Zelenskyy fired the head of the country’s security service and its prosecutor general on Sunday, citing hundreds of criminal proceedings into treason and collaboration by people within their departments. “In particular, more than 60 employees of the prosecutor’s office and the SBU have remained in the occupied territory and work against our state,” Zelenskyy said. “Such an array of crimes against the foundations of the state’s national security, and the links recorded between Ukrainian security forces and Russian special services raise very serious questions about their respective leaders,’’ he said in his nightly video address to the nation. He dismissed Prosecutor General Iryna Venediktova, and replaced her with her deputy Oleksiy Symonenko. He also dismissed Ivan Bakanov, a childhood friend and former business partner who headed Ukraine’s security service, the SBU. Bakanov had come under growing criticism recently over security breaches; Politico cited several unidentified Ukrainian and Western sources last month saying Zelenskyy was looking to replace him. Meanwhile, Russian missiles hit industrial facilities earlier Sunday at Mykolaiv, a strategic city in southern Ukraine. Mayor Oleksandr Senkevych said the missiles struck an industrial and infrastructure facility. Mykolaiv is a key shipbuilding center along the Southern Bug river and has faced regular Russian missile strikes in recent weeks as the Russians have sought to soften Ukrainian defenses.