Soviet leader Nikita Khrushchev and US Vice-President Richard Nixon have had a tense exchange of words about the merits of communism versus capitalism. This is the latest and most public of a series of impromptu debates between the two leaders which started yesterday on Mr Nixon's arrival in the USSR at the start of his 11-day visit. This time, the two men were touring the American trade exhibition in Moscow's Sokolniki Park ahead of its opening this evening. They stopped in front of a mock-up American kitchen displaying the latest gadgets - washing machines, toasters and juicers. Mr Khrushchev dismissed the exhibits and said: "You Americans expect that the Soviet people will be amazed. It is not so. We have all these things in our new flats." Mr Nixon replied: "We do not claim to astonish the Soviet people. We hope to show our right to choose. We do not wish to have decisions made at the top by government officials who say that all homes should be built in the same way." Reporters, government officials and workmen putting the finishing touches to the stands looked on amazed and then began to applaud their respective leaders. Mr Khrushchev went on to demand both sides remove "foreign bases". "The one who is for putting an end to foreign bases is for peace. The one who is not, is for war," he said. Mr Nixon retorted: "The moment we place either one of these powerful nations, through an ultimatum, in a position where they have no choice but to accept dictation or fight, then you are playing with the most destructive power in the world." Pointing his finger just inches from Mr Nixon's face, Mr Khrushchev replied sternly, "Who is giving the ultimatum?" He said Russia would answer threat with threat and had the means to do so. "Ours are better than yours," he said, referring to Russia's rockets. "We are well aware of that. We have some too," said Mr Nixon. In the end, Mr Nixon apologised for being a poor host and the two men agreed to thank the exhibit hostess for letting them argue in her kitchen. The exhibition was formally opened this evening, with Mr Nixon passing on a message of goodwill from President Eisenhower and Mr Khrushchev inviting the president to visit the USSR.