COLD FRONT HITSTHE G-7:

No sooner had the leaders of thebig seven economic powers arrived in Halifax, Nova Scotia today, than President Clinton and Japanese Prime Minister Tomiichi Murayama were trading tough talk about their trade standoff. Clinton refused to budge: "Billions of dollars in American exports and thousands of jobs are at stake," Clinton said of the automobile dispute, insisting that he would imposeunprecedented trade sanctions against Japanif the standoff continues past June 28. Murayama replied that the two allies should not conduct business "with both of our fists raised."