Concerned by the whereabouts of missiles dating from the clash between leftist Sandinistas and contra rebels in the 1980s, the US this week sent a mission to Nicaragua to review President Enrique Bolano's progress on his pledge to find and eliminate them.
But after a meeting with the US team on Wednesday, Defence Minister Jose Adan Guerra said not all missiles would be destroyed.
"The intention, the clear and firm will of the government is precisely to continue to dispose of the excess missiles while retaining a strategic reserve of 20% of the total so as to not undercut the state's defence capacity," Guerra said.
"We reached specific agreements so as to ease any concerns, doubts or worries there might be on the US part," he said, stressing the US mission was convinced "the missiles are stored perfectly safely".
The SA-7s were purchased by the Nicaraguan Sandinista government between 1979 and 1990 to battle the US-backed contras.
The US mission is led by Rose Likins, the acting assistant secretary for political and military affairs.