While seeking solutions to the complex budget and force structure issues, Aspin found himself beset with difficult regional problems and conflicts that demanded decisions and action. In NATO he pushed the U.S.-sponsored "Partnership for Peace" program to bring together NATO members and nonmembers for military activities, including training maneuvers, equipment sharing, search and rescue, antiterrorist efforts, environmental cleanup, and peacekeeping operations. At a meeting in Brussels in December 1993 the NATO defense ministers agreed to consider for future alliance membership those non-NATO nations that participated in the program. Russian President Boris Yeltsin warned that attempts to bring Eastern European nations into NATO would threaten his country's strategic interests and endanger hopes for the former Soviet bloc's reconciliation with the West. Yeltsin argued that enlarging NATO would reawaken old Russian concerns about encirclement and possibly weaken the cause of democratic reform.