U.S. Vice President Joseph Biden spoke Thursday with Ukrainian Prime Minister Arseniy Yatsenyuk about the situation in eastern Ukraine and the passage of key economic and governance reform legislation in Kiev, the White House said. Biden "expressed condolences for the loss of life in the mine accident in Donetsk Oblast and for the casualties sustained due to artillery fire along the line of contact, and regretted the refusal of Russia-backed separatists to allow Ukrainian rescue teams access to the site of the mine accident," the White House said in a statement late Thursday. The U.S. vice president congratulated Yatsenyuk on the passage of "crucial reform legislation ... that will help Ukraine return to economic health and pave the way for additional ... financial support from the international community," the White House wrote. The two leaders "expressed their concern regarding the refusal of Russia-backed separatists to allow for unimpeded access for OSCE (Organization for Security and Cooperation in Europe) monitors to the territory they control, as called for in the Minsk Implementation Plan," the statement said. Biden and Yatsenyuk also "expressed their concern about continued separatist attacks against Ukrainian forces and civilian areas," the White House said.