Evangelist Billy Graham, on a 10-day visit to East Germany, said it is his Christian duty to warn of the threat of nuclear war.

In a statement addressed to the East German people he added, "I have been calling for what I call SALT 10, which is the total destruction of all weapons of mass destruction. Can we ever come to that point? It is possible. But knowing human nature as I know it and as the Bible teaches it, it is not very hopeful. But we must work in that direction."

SALT 10 was an allusion to the strategic arms limitation treaties. President Reagan has ordered SALT II scrapped, and negotiations with the Soviet Union are under way toward a replacement treaty.

The trip to East Germany, which will be followed by one to Czechoslovakia, is Graham's second visit to a Communist-ruled country in five months. In May, the 63-year-old evangelist went to the Soviet Union to address a conference of religious leaders and to speak out against the nuclear arms race.

He drew Western criticism during the trip for saying he he had seen no evidence of religious persecution while in the Soviet Union.

Graham said he came to East Germany in part as a proclaimer of the gospel of Jesus Christ. "I am here to proclaim his message, both privately and publicly as opportunity may be provided."