On the eve of his two-day Nuclear Security Summit, President Obama laid out his intentions for the 47-country conference. Prior to meeting with South African President Jacob Zuma, Obama cited "the possibility of a terrorist organization obtaining a nuclear weapon" as "the single biggest threat to U.S. security, both short term, medium term and long term." He then stated that the principal focus of the summit is to get other nations on board with a specific timeline for locking-down nukes. "One of the things that I'm very pleased about is that countries have embraced this goal and they’re coming to this summit, not just talking about general statements of support but rather very specific approaches to how we can solve this profound international problem, " Obama said. He also praised South Africa for having dismantled its nuclear program and supporting non-proliferation issues.