Leaders of the world's richest nations began their 16th economic summit today, urged by President Bush to harness ``the power and energy of free wills and free markets'' to bolster the troubled economies of Eastern Europe and the Soviet Union. The seven leaders were deeply divided on how and when to provide financial assistance sought by Mikhail Gorbachev, but officials said a team of western bankers and other experts would be sent to assess Soviet needs. As the meetings began, the leaders lined up ``about half on one side, and half on the other'' over how to extend financial assistance to Mikhail Gorbachev, said White House chief of staff John Sununu. Bush has said he has ``big problems'' with extending direct aid to Moscow until it reduces military spending, moves more forcefully toward a free-market system and curtails the $5 billion a year subsidy to Cuba. A Gorbachev aide said Monday that western aid must be unconditional, explaining, ``We aren't taking orders.'' Bush met this morning with Francois Mitterrand and a French spokesman said both men stuck to their position: Bush opposes direct aid _ at least for now _ while Mitterrand favors ``all aid that is serious and useful.'' Officials said the leaders would approve an assessment team to recommend applications for western assistance. Sununu said the study might be conducted by a mixture of western financing agencies, including the World Bank and the International Monetary Fund. Bush is offering the Soviets technical assistance for transportation and agriculture and advice on developing free-market mechanisms. Sununu pointed out that the Soviets currently lose almost half their grain crop through faulty storage. Sununu noted that different countries view Soviet circumstances in different ways, perhaps a hint that Bush will not staunchly oppose direct aid from France, West Germany and Italy _ nations that are ready to proceed. Also meeting here are leaders from Britain, Japan, Canada and the European Economic Community. ``We are called upon as allies and as friends to work toward decisions that will bring new stability and prosperity to the world, by tapping the power and energy of free wills and free markets,'' Bush said in a statement opening the summit. ``These economic summits have become a framework for frank, constructive dialogue, a dialogue for progress that I believe will be advanced greatly in these next three days. A new world of freedom lays before us. Hopeful. Confident. A world where peace endures, where commerce has conscience, where all that seems possible is possible. ``So let us begin, in good faith, to set the stage for the new millennium.'' Soviet aid questions were a highly charged and undecided issue as the three-day summit began. Decisions were likely to come Wednesday in a final communique. From Moscow came a fresh plea for financial assistance. Foreign Minister Eduard Shevardnadze told reporters at the Communist Party Congress,``I feel it would be advantageous, for us and the West.'' He said Moscow was looking to the west for ``credit, technical cooperation, personnel training, joint ventures and joint projects.'' Meanwhile, the summit partners faced a tangle of their own differences over trade and the environment. Europeans are resisting Bush's demand for phasing out farm subsidies over the next 10 years and, together with Canada, are pushing for agreement on new steps to halt global warming. Sununu sniped at European critics of Bush's go-slow policy on curbing carbon dioxide and other pollutants blamed for warming the global environment. ``I think West Germany got a lot of good grades for rhetoric,'' he said on ABC. ``If you take a good look at what the United States has actually done in terms of cleaning up our environment ... I don't think the United States has to take a back seat to anyone.'' Yet, a prominent U.S. environmental group, the Wilderness Society, quickly chimed in to say, ``the U.S. gets a failing grade, no matter how Governor Sununu tries to rejigger the numbers.'' Before calling the summit into session on the campus of Rice University, Bush met separately with Mitterand and West German Chancellor Helmut Kohl to discuss their $15-billion aid proposal for Moscow. The world has changed dramatically since the last economic summit in Paris. At that time, the West was considering a limited aid package to encourage the beginings of reform efforts in Poland and Hungary. Since that time the Berlin Wall has crumbled and most of the communist nations of Eastern Europe have been swept away, leaving the West groping for a way to respond to the dramatic changes. Treasury Secretary Nicholas Brady said today the chief message from Houston will be to urge East European nations to undertake necessary economic reforms before they receive Western assistance. ``There's no sense in pouring money into a system that isn't ready to receive it,'' he said on NBC.'' Despite temperatures in the 90s and humidity topping 80 percent, the city of Houston went all out to welcome the heads of government, their contingents and hordes of reporters. Air conditioning was pumped onto the outddor platform to make the arrival ceremony comfortable for the leaders. Bush was host Sunday night to a pre-summit rodeo, complete with bareback riding, barrel racing and a calf scramble. Japan's Toshiki Kaifu, a first-time summiteer, waived his cowboy hat as if he'd been doing it all his life. Mitterrand, Italian Prime Minister Giulio Andreotti and Kohl delayed their arrival until today. Kohl was in Rome to watch his West German team win soccer's World Cup; Andreotti was there to present it. Bush had been in Houston since Friday, arriving from London, where he saw the NATO allies adopt a U.S. proposal to rewrite NATO's war-fighting strategy as a way of lessening tensions with the Soviet Union. Bush, as summit host, received a letter from Gorbachev appealing for western help. Gorbachev's latest plea was expected to be aired fully during a working dinner tonight. Pressing the Soviet case, foreign ministry spokesman Gennady Gerasimov said Moscow was shrinking its military and moving toward a market-price system that would curtail Moscow's huge subsidies to Cuba.