South Africa was praised by US President Barack Obama on Sunday for voluntarily dismantling its nuclear weapons programme as he met with South African President Jacob Zuma on the eve of a major summit on nuclear terrorism.

The two leaders have met for the first time Washington since Zuma's 2009 election.

Obama used the opportunity to outline the goals of the summit Monday and Tuesday, which is drawing 38 leaders and top officials from another nine countries.

Obama said, "The single biggest threat to US security, both short term, medium term and long term, would be the possibility of a terrorist organization obtaining a nuclear weapon."

He further said, "If there was ever a detonation in New York City, or London, or Johannesburg, the ramifications economically, politically and from a security perspective would be devastating."

White House officials also said that the central focus of the summit is to get commitments from the top levels of government to recognize nuclear terrorism as a major global threat, to get commitments to current conventions on nuclear terrorism and to develop a work plan.

South Africa had been developing a nuclear weapons program from the 1960s onward, reportedly in collaboration with Israel, but as the end of apartheid loomed in the 1990s, the South African government dismantled all its nuclear weapons.

Obama said, "South Africa has special standing in being a moral leader on this issue."

A White House official who talked to reporters, also noted that the move brought South Africa "greater security and prosperity" in the international community. (With Inputs from Agencies)